Servo pattern recording device, magnetic tape, magnetic tape cartridge, magnetic tape drive, magnetic tape system, detection device, servo pattern recording method, and manufacturing method of magnetic tape

ABSTRACT

A plurality of gap patterns are formed on a front surface of a substrate along a direction corresponding to a width direction of a magnetic tape. The first straight line region has a steeper inclined angle with respect to the first imaginary straight line than the second straight line region. Positions of both ends of the first straight line region and positions of both ends of the second straight line region are aligned in a direction corresponding to a width direction of a magnetic tape. Positions of the plurality of gap patterns are aligned in a longitudinal direction of the magnetic tape. A pulse signal is supplied to each of the plurality of gap patterns with a delay of a predetermined time from one side to the other side in a direction in which the plurality of gap patterns are arranged.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application No.2021-160003, filed Sep. 29, 2021, and Japanese Patent Application No.2022-075195, filed Apr. 28, 2022, the disclosures of which areincorporated herein by reference in their entireties.

BACKGROUND Technical Field

The technology of the present disclosure relates to a servo patternrecording device, a magnetic tape, a magnetic tape cartridge, a magnetictape drive, a magnetic tape system, a detection device, an inspectiondevice, a servo pattern recording method, and a manufacturing method adetection method and an inspection method of a magnetic tape.

Related Art

U.S. Pat. No. 8,094,402B raises a problem in a magnetic tape device thata read and/or write error occurs in a case in which a tape does not passthrough a head at appropriate tension and/or a skew angle. In order tosolve this problem, a system disclosed in U.S. Pat. No. 8,094,402Bincludes a head having an array of at least one of a reader or a writer,a drive mechanism that causes a magnetic recording tape to pass on thehead, and a skew induction mechanism bonded to the head, in which a skewangle of a vertical axis of the array with respect to a directionperpendicular to a direction in which the tape is moved on the head, anda controller that communicates with the head is adjusted. In addition,the system disclosed in U.S. Pat. No. 8,094,402B determines a tapedimension stable state of the tape, adjusts the skew angle in adirection away from a normal line with respect to a tape movementdirection, and reduces the tension of the tape on the entire head in acase in which the tape dimension stable state is in a contraction state.

U.S. Pat. No. 6,781,784B discloses a method of performing reading byselectively using a reading element offset in a vertical direction withrespect to a data track of a magnetic tape in which distortion in alateral direction occurs. The reading element is a part of a tape headthat has an azimuthal angle with respect to the tape and creates anoffset in the lateral direction between the reading elements. The offsetin the lateral direction is used to minimize the effects of thedistortion of the tape in the lateral direction.

JP2009-123288A discloses a head device comprising a head unit on which aplurality of magnetic elements that each perform at least one ofreproduction of data recorded in a plurality of data tracks provided ina magnetic tape or recording of data in each data track are arranged tobe parallel on a first straight line at equal intervals, a movingmechanism that moves the head unit, and a controller that executes atracking control of causing the magnetic elements to be on-tracked onthe data tracks, respectively, by moving the head unit by the movingmechanism. In the head device disclosed in JP2009-123288A, the movingmechanism is configured to perform rotational movement of rotationallymoving the head unit in an orientation of increasing or decreasing anangle formed by a second straight line along a width of the magnetictape line and the first straight line, and, during the execution of thetracking control, the controller causes each magnetic element to beon-tracked on each data track by rotationally moving and driving thehead unit by the moving mechanism by an increasing or decreasing amountof the angle in accordance with a change of an interval between the datatracks.

JP2000-260014A discloses a method of forming a servo trackconfiguration, the method including a step of forming at least one servotrack that has a width, and a recording step of repeatedly recording aservo pattern in the servo track, in which the recording step includes astep of repeating simultaneous recording of first and second referencepattern lines and a track pattern line in the servo track. Each of thefirst and second reference pattern lines has an identical predeterminedgeometry and extends across the width of the servo track, and furtherthe track pattern line has a predetermined geometry that is differentthan the predetermined geometry of the first and second referencepattern lines and extends across the width of the servo track.

JP2020-140744A discloses a magnetic tape reading apparatus that includesan acquisition unit that acquires information on linearity of a servopattern to be recorded on a servo band of a magnetic tape included in amagnetic tape cartridge from the magnetic tape cartridge, a readingelement unit in which at least two reading elements each of which readsdata by a linear scanning method from a specific track region includinga reading target track in a track region included in the magnetic tapeare disposed in a state of being adjacent to each other, a servo readingelement that reads the servo pattern, a control unit that performscontrol of positioning the reading element unit by using a read signalof the servo pattern read by the servo reading element and theinformation on the linearity acquired by the acquisition unit, aderivation unit that derives a deviation amount between positions of themagnetic tape and the reading element unit by using the read signal ofthe servo pattern in a state where the control unit performs control,and an extraction unit that extracts data recorded on the reading targettrack from a reading result by performing a waveform equalizationprocess to each reading result for the reading elements in accordancewith the deviation amount derived by the derivation unit.

SUMMARY

One embodiment according to the technology of the present disclosure isto provide a servo pattern recording device, a magnetic tape, a magnetictape cartridge, a magnetic tape drive, a magnetic tape system, adetection device, an inspection device, a servo pattern recordingmethod, and a manufacturing method, a detection method and an inspectionmethod of a magnetic tape capable of obtaining a servo signal havinghigh reliability.

An first aspect according to the technology of the present disclosurerelates to a servo pattern recording device comprising a pulse signalgenerator, and a servo pattern recording head, in which the pulse signalgenerator generates a pulse signal, the servo pattern recording head hasa substrate and a plurality of gap patterns formed on a front surface ofthe substrate, and records a plurality of servo patterns in a widthdirection of a magnetic tape by applying a magnetic field to themagnetic tape from the plurality of gap patterns in response to thepulse signal, the plurality of gap patterns are formed on the frontsurface along a direction corresponding to the width direction, the gappatterns are at least one straight line region pair, a first straightline region, which is one straight line region of the straight lineregion pair, and a second straight line region, which is the otherstraight line region of the straight line region pair, are inclined inopposite directions with respect to a first imaginary straight linealong the direction corresponding to the width direction on the frontsurface, the first straight line region has a steeper inclined anglewith respect to the first imaginary straight line than the secondstraight line region, positions of both ends of the first straight lineregion and positions of both ends of the second straight line region arealigned in the direction corresponding to the width direction of themagnetic tape, positions of the plurality of gap patterns in alongitudinal direction of the magnetic tape are aligned on the frontsurface, and the pulse signal generator supplies the pulse signal with adelay of a predetermined time to each of the plurality of gap patternsfrom one side to the other side in a direction in which the plurality ofgap patterns are arranged.

A second aspect according to the technology of the present disclosurerelates to the servo pattern recording device according to the firstaspect, in which the substrate is formed in a rectangular parallelepipedshape, and crosses the magnetic tape in a direction orthogonal to thelongitudinal direction of the magnetic tape.

A third aspect according to the technology of the present disclosurerelates to the servo pattern recording device according to the secondaspect, in which the front surface is formed in a rectangular shapehaving a long side and a short side, and a length of the short side is alength in which the plurality of servo patterns are contained.

A fourth aspect according to the technology of the present disclosurerelates to the servo pattern recording device according to the thirdaspect, in which the substrate is disposed on the magnetic tape in aposture in which an orientation of the long side and the longitudinaldirection of the magnetic tape are orthogonal to each other.

A fifth aspect according to the technology of the present disclosurerelates to the servo pattern recording device according to any one ofthe first to fourth aspects, in which a total length of the firststraight line region is shorter than a total length of the secondstraight line region.

A sixth aspect according to the technology of the present disclosurerelates to the servo pattern recording device according to any one ofthe first to fifth aspects, in which a geometrical characteristic of thestraight line region pair on the front surface corresponds to ageometrical characteristic in which positions of both ends of oneimaginary straight line region of a pair of imaginary straight lineregions and positions of both ends of the other imaginary straight lineregion are aligned in the direction corresponding to the width directionin a case in which an entirety of the pair of imaginary straight lineregions is inclined with respect to the first imaginary straight line byinclining, with respect to the first imaginary straight line, a symmetryaxis of the pair of imaginary straight line regions inclinedline-symmetrically with respect to the first imaginary straight line.

A seventh aspect according to the technology of the present disclosurerelates to the servo pattern recording device according to any one ofthe first to sixth aspects, in which a plurality of servo bands areformed on the magnetic tape along the width direction, servo patternscorresponding to each other between the servo bands deviate from eachother at a predetermined interval in the longitudinal direction of themagnetic tape, between the servo bands adjacent to each other in thewidth direction, and the predetermined time is determined in accordancewith the predetermined interval.

An eighth aspect according to the technology of the present disclosurerelates to the servo pattern recording device according to the seventhaspect, in which a plurality of servo bands are formed on the magnetictape along the width direction, the servo bands are divided by a framedefined based on at least one set of the servo patterns, and thepredetermined interval is defined based on an angle formed by the framesthat have a correspondence relationship between the servo bands adjacentto each other in the width direction and the first imaginary straightline, and a pitch between the servo bands adjacent to each other in thewidth direction.

A ninth aspect according to the technology of the present disclosurerelates to the servo pattern recording device according to the seventhaspect, in which a plurality of servo bands are formed on the magnetictape along the width direction, the servo bands are divided by a framedefined based on at least one set of the servo patterns, and thepredetermined interval is defined based on an angle formed by the framesthat have no correspondence relationship between the servo bandsadjacent to each other in the width direction and the first imaginarystraight line, a pitch between the servo bands adjacent to each other inthe width direction, and a total length of the frame in the longitudinaldirection.

A tenth aspect according to the technology of the present disclosurerelates to a magnetic tape in which the plurality of servo patterns arerecorded by the servo pattern recording device according to any one ofthe first to ninth aspects.

An eleventh aspect according to the technology of the present disclosurerelates to a magnetic tape cartridge comprising the magnetic tapeaccording to the tenth aspect, and a case in which the magnetic tape isaccommodated.

A twelfth aspect according to the technology of the present disclosurerelates to a magnetic tape drive comprising a travel mechanism thatcauses the magnetic tape according to the tenth aspect to travel along apredetermined path, and a magnetic head including a plurality of servoreading elements that read the servo patterns on the predetermined pathin a state in which the magnetic tape is caused to travel by the travelmechanism, in which the plurality of servo reading elements are arrangedalong the longitudinal direction of the magnetic head, and the magnetichead is disposed in a posture in which a second imaginary straight linealong the longitudinal direction of the magnetic head is inclined withrespect to a traveling direction of the magnetic tape.

A thirteenth aspect according to the technology of the presentdisclosure relates to a magnetic tape system comprising the magnetictape according to the tenth aspect, and a magnetic tape drive on which amagnetic head including a plurality of servo reading elements that readthe servo patterns on a predetermined path in a state in which themagnetic tape is caused to travel along the predetermined path ismounted, in which the plurality of servo reading elements are arrangedalong the longitudinal direction of the magnetic head, and the magnetichead is disposed in a posture in which a third imaginary straight linealong the longitudinal direction of the magnetic head is inclined withrespect to a traveling direction of the magnetic tape.

A fourteenth aspect according to the technology of the presentdisclosure relates to a detection device comprising a processor, inwhich the processor detects a servo signal, which is a result of readingthe servo pattern by a servo reading element from the magnetic tapeaccording to the tenth aspect, by using an autocorrelation coefficient.

A fifteenth aspect according to the technology of the present disclosurerelates to a servo pattern recording method comprising generating apulse signal, and recording, by the servo pattern recording head havinga substrate and a plurality of gap patterns formed on a front surface ofthe substrate, a plurality of servo patterns in a width direction of amagnetic tape by applying a magnetic field to the magnetic tape from theplurality of gap patterns in response to the pulse signal, in which theplurality of gap patterns are formed on the front surface along adirection corresponding to the width direction, the gap patterns are atleast one straight line region pair, a first straight line region, whichis one straight line region of the straight line region pair, and asecond straight line region, which is the other straight line region ofthe straight line region pair, are inclined in opposite directions withrespect to a first imaginary straight line along the directioncorresponding to the width direction on the front surface, the firststraight line region has a steeper inclined angle with respect to thefirst imaginary straight line than the second straight line region,positions of both ends of the first straight line region and positionsof both ends of the second straight line region are aligned in thedirection corresponding to the width direction of the magnetic tape,positions of the plurality of gap patterns in a longitudinal directionof the magnetic tape are aligned on the front surface, and the servopattern recording method further includes supplying the pulse signalwith a delay of a predetermined time to each of the plurality of gappatterns from one side to the other side in a direction in which theplurality of gap patterns are arranged.

A sixteenth aspect according to the technology of the present disclosurerelates to a manufacturing method of a magnetic tape, the methodcomprising recording the plurality of servo patterns in the magnetictape according to the servo pattern recording method according to thefifteenth aspect, and winding the magnetic tape.

A seventeenth aspect according to the technology of the presentdisclosure relates to an inspection device including a detection devicethat is the detection device according to the fourteenth aspect and thatis used together with the servo pattern recording device according tothe first aspect, and an inspection processor that inspects a servo bandon which the servo pattern is recorded in the magnetic tape based on theservo signal detected by the detection device.

A eighteenth aspect according to the technology of the presentdisclosure relates to a detection method used together with the servopattern recording method according to the fifteenth aspect, the methodincluding detecting a servo signal, which is a result obtained byreading the servo pattern by a servo reading element from the magnetictape according to the tenth aspect, using an autocorrelationcoefficient.

An nineteenth aspect according to the technology of the presentdisclosure relates to an inspection method including inspecting a servoband on which the servo pattern is recorded in the magnetic tape basedon the servo signal detected by the detection method according to theeighteenth aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an example of a configuration of amagnetic tape system according to an embodiment.

FIG. 2 is a schematic perspective view of an example of an appearance ofa magnetic tape cartridge according to the embodiment.

FIG. 3 is a schematic configuration diagram showing an example of ahardware configuration of a magnetic tape drive according to theembodiment.

FIG. 4 is a schematic perspective view showing an example of an aspectin which a magnetic field is released by a noncontact read/write devicefrom a lower side of the magnetic tape cartridge according to theembodiment.

FIG. 5 is a schematic configuration diagram showing an example of thehardware configuration of the magnetic tape drive according to theembodiment.

FIG. 6 is a conceptual diagram showing an example of an aspect in whicha state in which a magnetic head is disposed on a known magnetic tape inthe related art is observed from a front surface side of the magnetictape.

FIG. 7 is a conceptual diagram showing an example of an aspect in whichthe known magnetic tape in the related art before and after a width ofthe magnetic tape contracts is observed from the front surface side ofthe magnetic tape.

FIG. 8 is a conceptual diagram showing an example of an aspect in whicha state in which the magnetic head is skewed on the known magnetic tapein the related art is observed from the front surface side of themagnetic tape.

FIG. 9 is a conceptual diagram showing an example of an aspect in whichthe magnetic tape according to the embodiment is observed from the frontsurface side of the magnetic tape.

FIG. 10 is a conceptual diagram showing an example of a relationshipbetween a geometrical characteristic of an actual servo pattern and ageometrical characteristic of an imaginary servo pattern.

FIG. 11 is a conceptual diagram showing an example of an aspect in whicha state in which frames corresponding to each other between the servobands adjacent to each other in the width direction of the magnetic tapeaccording to the embodiment deviate from each other at a predeterminedinterval is observed from the front surface side of the magnetic tape.

FIG. 12 is a conceptual diagram showing an example of an aspect in whicha state in which the servo pattern is read by a servo reading elementprovided in the magnetic head that is not skewed on the magnetic tapeaccording to the embodiment is observed from the front surface side ofthe magnetic tape.

FIG. 13 is a conceptual diagram showing an example of an aspect in whicha state in which the servo pattern is read by the servo reading elementprovided in the magnetic head that is skewed on the magnetic tapeaccording to the embodiment is observed from the front surface side ofthe magnetic tape.

FIG. 14 is a conceptual diagram showing an example of a function of acontrol device provided in the magnetic tape drive according to theembodiment.

FIG. 15 is a conceptual diagram showing an example of processingcontents of a position detection unit and a controller provided in thecontrol device provided in the magnetic tape drive according to theembodiment.

FIG. 16 is a conceptual diagram showing an example of a configuration ofa servo writer according to the embodiment.

FIG. 17 is a conceptual diagram showing an example of a relationshipbetween a pulse signal generator and a servo pattern recording headprovided in the servo writer according to the embodiment, and an exampleof an aspect in which a state in which the servo pattern recording headprovided in the servo writer according to the embodiment is disposed onthe magnetic tape is observed from the front surface side of themagnetic tape (that is, a rear surface side of the servo patternrecording head).

FIG. 18 is a conceptual diagram showing an example of an aspect in whicha state in which the servo pattern recording head provided in the servowriter according to the embodiment is disposed on the magnetic tape isobserved from the front surface side of the magnetic tape (that is, therear surface side of the servo pattern recording head).

FIG. 19 is a conceptual diagram showing an example of a relationshipbetween a geometrical characteristic of an actual gap pattern and ageometrical characteristic of an imaginary gap pattern.

FIG. 20 is a conceptual diagram showing an example of an aspect in whicha state in which the servo pattern recording head according to a firstcomparative example is disposed on the magnetic tape is observed fromthe front surface side of the magnetic tape (that is, the rear surfaceside of the servo pattern recording head).

FIG. 21 is a conceptual diagram showing an example of an aspect in whicha state in which the servo pattern recording head according to a secondcomparative example is disposed on the magnetic tape is observed fromthe front surface side of the magnetic tape (that is, the rear surfaceside of the servo pattern recording head).

FIG. 22 is a conceptual diagram showing a first modification example ofthe magnetic tape according to the embodiment (conceptual diagramshowing an example of an aspect in which the magnetic tape according tothe first modification example is observed from the front surface sideof the magnetic tape).

FIG. 23 is a conceptual diagram showing an example of an aspect of theservo pattern included in the magnetic tape according to the firstmodification example.

FIG. 24 is a conceptual diagram showing the first modification exampleof the servo pattern recording head provided in the servo writeraccording to the embodiment (conceptual diagram showing an example of anaspect in which a state in which the servo pattern recording headaccording to the first modification example is disposed on the magnetictape is observed from the front surface side of the magnetic tape (thatis, the rear surface side of the servo pattern recording head)).

FIG. 25 is a conceptual diagram showing a second modification example ofthe magnetic tape according to the embodiment (conceptual diagramshowing an example of an aspect in which the magnetic tape according tothe second modification example is observed from the front surface sideof the magnetic tape).

FIG. 26 is a conceptual diagram showing an example of an aspect of theservo pattern included in the magnetic tape according to the secondmodification example.

FIG. 27 is a conceptual diagram showing the second modification exampleof the servo pattern recording head provided in the servo writeraccording to the embodiment (conceptual diagram showing an example of anaspect in which a state in which the servo pattern recording headaccording to the second modification example is disposed on the magnetictape is observed from the front surface side of the magnetic tape (thatis, the rear surface side of the servo pattern recording head)).

FIG. 28 is a conceptual diagram showing an example of an aspect in whicha state in which frames corresponding to each other between the servobands adjacent to each other in the width direction of the magnetic tapeaccording to the embodiment deviate from each other at a predeterminedinterval is observed from the front surface side of the magnetic tape.

DETAILED DESCRIPTION

In the following, examples of embodiments of a servo pattern recordingdevice, a magnetic tape, a magnetic tape cartridge, a magnetic tapedrive, a magnetic tape system, a detection device, an inspection device,a servo pattern recording method, and a manufacturing method, adetection method and an inspection method of a magnetic tape accordingto the technology of the present disclosure will be described withreference to the attached drawings.

First, the terms used in the following description will be described.

NVM refers to an abbreviation of “non-volatile memory”. CPU refers to anabbreviation of “central processing unit”. RAM refers to an abbreviationof “random access memory”. EEPROM refers to an abbreviation of“electrically erasable and programmable read only memory”. SSD refers toan abbreviation of “solid state drive”. HDD refers to an abbreviation of“hard disk drive”. ASIC refers to an abbreviation of “applicationspecific integrated circuit”. FPGA refers to an abbreviation of“field-programmable gate array”. PLC is an abbreviation for“programmable logic controller”. IC refers to an abbreviation of“integrated circuit”. RFID refers to an abbreviation of “radio frequencyidentifier”. BOT refers to an abbreviation of “beginning of tape”. EOTrefers to an abbreviation of “end of tape”. UI refers to an abbreviationof “user interface”. WAN refers to an abbreviation of “wide areanetwork”. LAN refers to an abbreviation of “local area network”.

As an example, as shown in FIG. 1 , a magnetic tape system 10 comprisesa magnetic tape cartridge 12 and a magnetic tape drive 14. A magnetictape cartridge 12 is loaded into the magnetic tape drive 14. Themagnetic tape cartridge 12 accommodates a magnetic tape MT. The magnetictape drive 14 pulls out the magnetic tape MT from the loaded magnetictape cartridge 12, and records data in the magnetic tape MT and readsdata from the magnetic tape MT while causing the pulled out magnetictape MT to travel.

In the present embodiment, the magnetic tape MT is an example of a“magnetic tape” according to the technology of the present disclosure.In addition, in the present embodiment, the magnetic tape system 10 isan example of a “magnetic tape system” according to the technology ofthe present disclosure. In addition, in the present embodiment, themagnetic tape drive 14 is an example of a “magnetic tape drive” and a“detection device” according to the technology of the presentdisclosure. In addition, in the present embodiment, the magnetic tapecartridge 12 is an example of a “magnetic tape cartridge” according tothe technology of the present disclosure.

Next, an example of a configuration of the magnetic tape cartridge 12will be described with reference to FIGS. 2 to 4 . It should be notedthat, in the following description, for convenience of description, inFIGS. 2 to 4 , a loading direction of the magnetic tape cartridge 12into the magnetic tape drive 14 is indicated by an arrow A, a directionof the arrow A is defined as a front direction of the magnetic tapecartridge 12, and a side of the magnetic tape cartridge 12 in the frontdirection is defined as a front side of the magnetic tape cartridge 12.In the following description of the structure, “front” refers to thefront side of the magnetic tape cartridge 12.

In addition, in the following description, for convenience ofdescription, in FIGS. 2 to 4 , a direction of an arrow B orthogonal tothe direction of the arrow A is defined as a right direction, and a sideof the magnetic tape cartridge 12 in the right direction is defined as aright side of the magnetic tape cartridge 12. In the followingdescription of the structure, “right” refers to the right side of themagnetic tape cartridge 12.

In addition, in the following description, for convenience ofdescription, in FIGS. 2 to 4 , a direction opposite to the direction ofthe arrow B is defined as a left direction, and a side of the magnetictape cartridge 12 in the left direction is defined as a left side of themagnetic tape cartridge 12. In the following description of thestructure, “left” refers to the left side of the magnetic tape cartridge12.

In addition, in the following description, for convenience ofdescription, in FIGS. 2 to 4 , a direction orthogonal to the directionof the arrow A and the direction of the arrow B is indicated by an arrowC, a direction of the arrow C is defined as an upper direction of themagnetic tape cartridge 12, and a side of the magnetic tape cartridge 12in the upper direction is defined as an upper side of the magnetic tapecartridge 12. In the following description of the structure, “upper”refers to the upper side of the magnetic tape cartridge 12.

In addition, in the following description, for convenience ofdescription, in FIGS. 2 to 4 , a direction opposite to the frontdirection of the magnetic tape cartridge 12 is defined as a reardirection of the magnetic tape cartridge 12, and a side of the magnetictape cartridge 12 in the rear direction is defined as a rear side of themagnetic tape cartridge 12. In the following description of thestructure, “rear” refers to the rear side of the magnetic tape cartridge12.

In addition, in the following description, for convenience ofdescription, in FIGS. 2 to 4 , a direction opposite to the upperdirection of the magnetic tape cartridge 12 is defined as a lowerdirection of the magnetic tape cartridge 12, and a side of the magnetictape cartridge 12 in the lower direction is defined as a lower side ofthe magnetic tape cartridge 12. In the following description of thestructure, “lower” refers to the lower side of the magnetic tapecartridge 12.

As an example, as shown in FIG. 2 , the magnetic tape cartridge 12 has asubstantially rectangular shape in a plan view, and comprises abox-shaped case 16. The case 16 is an example of a “case” according tothe technology of the present disclosure. The magnetic tape MT isaccommodated in the case 16. The case 16 is made of resin, such aspolycarbonate, and comprises an upper case 18 and a lower case 20. Theupper case 18 and the lower case 20 are bonded by welding (for example,ultrasound welding) and screwing in a state in which a lower peripheraledge surface of the upper case 18 and an upper peripheral edge surfaceof the lower case 20 are brought into contact with each other. Thebonding method is not limited to welding and screwing, and other bondingmethods may be used.

A sending reel 22 is rotatably accommodated inside the case 16. Thesending reel 22 comprises a reel hub 22A, an upper flange 22B1, and alower flange 22B2. The reel hub 22A is formed in a cylindrical shape.The reel hub 22A is a shaft center portion of the sending reel 22, has ashaft center direction along an up-down direction of the case 16, and isdisposed in a center portion of the case 16. Each of the upper flange22B1 and the lower flange 22B2 is formed in an annular shape. A centerportion of the upper flange 22B1 in a plan view is fixed to an upper endportion of the reel hub 22A, and a center portion of the lower flange22B2 in a plan view is fixed to a lower end portion of the reel hub 22A.It should be noted that the reel hub 22A and the lower flange 22B2 maybe integrally molded.

The magnetic tape MT is wound around an outer peripheral surface of thereel hub 22A, and an end portion of the magnetic tape MT in a widthdirection is held by the upper flange 22B1 and the lower flange 22B2.

An opening 16B is formed on a front side of a right wall 16A of the case16. The magnetic tape MT is pulled out from the opening 16B.

A cartridge memory 24 is provided in the lower case 20. Specifically,the cartridge memory 24 is accommodated in a right rear end portion ofthe lower case 20. An IC chip including an NVM is mounted on thecartridge memory 24. In the present embodiment, a so-called passive RFIDtag is adopted as the cartridge memory 24, and the read/write of variouspieces information is performed with respect to the cartridge memory 24in a noncontact manner.

The cartridge memory 24 stores management information for managing themagnetic tape cartridge 12. Examples of the management informationinclude information on the cartridge memory 24 (for example, informationfor specifying the magnetic tape cartridge 12), information on themagnetic tape MT (for example, information indicating a recordingcapacity of the magnetic tape MT, information indicating an outline ofthe data recorded in the magnetic tape MT, information indicating itemsof the data recorded in the magnetic tape MT, and information indicatinga recording format of the data recorded in the magnetic tape MT), andinformation on the magnetic tape drive 14 (for example, informationindicating a specification of the magnetic tape drive 14 and a signalused in the magnetic tape drive 14).

As an example, as shown in FIG. 3 , the magnetic tape drive 14 comprisesa transport device 26, a magnetic head 28, a control device 30, astorage 32, a UI system device 34, and a communication interface 35. Themagnetic tape drive 14 is loaded into the magnetic tape cartridge 12along the direction of the arrow A. In the magnetic tape drive 14, themagnetic tape MT is pulled out from the magnetic tape cartridge 12 andused.

The magnetic tape MT has a magnetic layer 29A, a base film 29B, and aback coating layer 29C. The magnetic layer 29A is formed on one surfaceside of the base film 29B, and the back coating layer 29C is formed onthe other surface side of the base film 29B. The data is recorded in themagnetic layer 29A. The magnetic layer 29A contains ferromagneticpowder. As the ferromagnetic powder, for example, ferromagnetic powdergenerally used in the magnetic layer of various magnetic recording mediais used. Preferable specific examples of the ferromagnetic powderinclude hexagonal ferrite powder. Examples of the hexagonal ferritepowder include hexagonal strontium ferrite powder and hexagonal bariumferrite powder. The back coating layer 29C is a layer containingnon-magnetic powder, such as carbon black. The base film 29B is alsoreferred to as a support, and is made of, for example, polyethyleneterephthalate, polyethylene naphthalate, or polyamide. It should benoted that a non-magnetic layer may be formed between the base film 29Band the magnetic layer 29A. In the magnetic tape MT, a surface on whichthe magnetic layer 29A is formed is a front surface 31 of the magnetictape MT, and a surface on which the back coating layer 29C is formed isa back surface 33 of the magnetic tape MT.

The magnetic tape drive 14 performs magnetic processing on the frontsurface 31 of the magnetic tape MT by using the magnetic head 28. Here,the magnetic processing refers to recording the data in the frontsurface 31 of the magnetic tape MT and reading the data (that is,reproducing the data) from the front surface 31 of the magnetic tape MT.In the present embodiment, the magnetic tape drive 14 selectivelyrecords the data in the front surface 31 of the magnetic tape MT andreads the data from the front surface 31 of the magnetic tape MT byusing the magnetic head 28. That is, the magnetic tape drive 14 is adevice that pulls out the magnetic tape MT from the magnetic tapecartridge 12, records the data in the front surface 31 of the pulled outmagnetic tape MT by using the magnetic head 28, or reads the data fromthe front surface 31 of the pulled out magnetic tape MT by using themagnetic head 28.

The control device 30 controls the entire magnetic tape drive 14. In thepresent embodiment, although the control device 30 is realized by anASIC, the technology of the present disclosure is not limited to this.For example, the control device 30 may be realized by an FPGA and/or aPLC. In addition, the control device 30 may be realized by the computerincluding a CPU, a flash memory (for example, an EEPROM and/or an SSD),and a RAM. In addition, the control device 30 may be realized bycombining two or more of an ASIC, an FPGA, a PLC, and a computer. Thatis, the control device 30 may be realized by a combination of a hardwareconfiguration and a software configuration. It should be noted that thecontrol device 30 is an example of a “processor” according to thetechnology of the present disclosure.

The storage 32 is connected to the control device 30, and the controldevice 30 writes various pieces of information to the storage 32 andreads out various pieces of information from the storage 32. Examples ofthe storage 32 include a flash memory and/or an HDD. The flash memoryand the HDD are merely examples, and any memory may be used as long asthe memory is a non-volatile memory that can be mounted on the magnetictape drive 14.

The UI system device 34 is a device having the reception function ofreceiving a command signal indicating a command from a user and thepresentation function of presenting the information to the user. Thereception function is realized by a touch panel, a hard key (forexample, a keyboard), and/or a mouse, for example. The presentationfunction is realized by a display, a printer, and/or a speaker, forexample. The UI system device 34 is connected to the control device 30.The control device 30 acquires the command signal received by the UIsystem device 34. The UI system device 34 presents various pieces ofinformation to the user under the control of the control device 30.

The communication interface 35 is connected to the control device 30. Inaddition, the communication interface 35 is connected to an externaldevice 37 via a communication network (not shown), such as a WAN and/ora LAN. The communication interface 35 controls the exchange of variouspieces of information (for example, the data to be recorded in themagnetic tape MT, the data read from the magnetic tape MT, and/or acommand signal given to the control device 30) between the controldevice 30 and the external device 37. It should be noted that examplesof the external device 37 include a personal computer and a mainframe.

The transport device 26 is a device that selectively transports themagnetic tape MT along a predetermined path in a forward direction and abackward direction, and comprises a sending motor 36, a winding reel 38,a winding motor 40, and a plurality of guide rollers GR. It should benoted that, here, the forward direction refers to a sending direction ofthe magnetic tape MT, and the backward direction refers to a rewindingdirection of the magnetic tape MT. In the present embodiment, thetransport device 26 is an example of a “travel mechanism” according tothe technology of the present disclosure.

The sending motor 36 rotates the sending reel 22 in the magnetic tapecartridge 12 under the control of the control device 30. The controldevice 30 controls the sending motor 36 to control a rotation direction,a rotation speed, a rotation torque, and the like of the sending reel22.

The winding motor 40 rotates the winding reel 38 under the control ofthe control device 30. The control device 30 controls the winding motor40 to control a rotation direction, a rotation speed, a rotation torque,and the like of the winding reel 38.

In a case in which the magnetic tape MT is wound by the winding reel 38,the control device 30 rotates the sending motor 36 and the winding motor40 such that the magnetic tape MT travels along the predetermined pathin the forward direction. The rotation speed, the rotation torque, andthe like of the sending motor 36 and the winding motor 40 are adjustedin accordance with a speed at which the magnetic tape MT is wound aroundthe winding reel 38. In addition, by adjusting the rotation speed, therotation torque, and the like of each of the sending motor 36 and thewinding motor 40 by the control device 30, the tension is applied to themagnetic tape MT. In addition, the tension applied to the magnetic tapeMT is controlled by adjusting the rotation speed, the rotation torque,and the like of each of the sending motor 36 and the winding motor 40 bythe control device 30.

It should be noted that, in a case in which the magnetic tape MT isrewound to the sending reel 22, the control device 30 rotates thesending motor 36 and the winding motor 40 such that the magnetic tape MTtravels along the predetermined path in the backward direction.

In the present embodiment, the tension applied to the magnetic tape MTis controlled by controlling the rotation speed, the rotation torque,and the like of the sending motor 36 and the winding motor 40, but thetechnology of the present disclosure is not limited to this. Forexample, the tension applied to the magnetic tape MT may be controlledby using a dancer roller, or may be controlled by drawing the magnetictape MT into a vacuum chamber.

Each of the plurality of guide rollers GR is a roller which guides themagnetic tape MT. The predetermined path, that is, a traveling path ofthe magnetic tape MT is determined by separately disposing the pluralityof guide rollers GR at positions straddling the magnetic head 28 betweenthe magnetic tape cartridge 12 and the winding reel 38.

The magnetic head 28 comprises a magnetic element unit 42 and a holder44. The magnetic element unit 42 is held by the holder 44 to come intocontact with the traveling magnetic tape MT. The magnetic element unit42 includes a plurality of magnetic elements.

The magnetic element unit 42 records the data in the magnetic tape MTtransported by the transport device 26, and reads the data from themagnetic tape MT transported by the transport device 26. Here, the datarefers to, for example, a servo pattern 58 (see FIG. 9 ) and the dataother than the servo pattern 58, that is, the data recorded in the databand DB (see FIG. 9 ).

The magnetic tape drive 14 comprises a noncontact read/write device 46.The noncontact read/write device 46 is disposed to face a back surface24A of the cartridge memory 24 on the lower side of the magnetic tapecartridge 12 in a state in which the magnetic tape cartridge 12 isloaded, and performs the read/write of the information with respect tothe cartridge memory 24 in a noncontact manner.

As an example, as shown in FIG. 4 , the noncontact read/write device 46releases a magnetic field MF from the lower side of the magnetic tapecartridge 12 toward the cartridge memory 24. The magnetic field MFpasses through the cartridge memory 24.

The noncontact read/write device 46 is connected to the control device30. The control device 30 outputs a control signal to the noncontactread/write device 46. The control signal is a signal for controlling thecartridge memory 24. The noncontact read/write device 46 generates themagnetic field MF in response to the control signal input from thecontrol device 30, and releases the generated magnetic field MF towardthe cartridge memory 24.

The noncontact read/write device 46 performs noncontact communicationwith the cartridge memory 24 via the magnetic field MF to performprocessing on the cartridge memory 24 in response to the control signal.For example, the noncontact read/write device 46 selectively performs,under the control of the control device 30, processing of reading theinformation from the cartridge memory 24 and processing of storing theinformation in the cartridge memory 24 (that is, processing of writingthe information to the cartridge memory 24).

As an example, as shown in FIG. 5 , the magnetic tape drive 14 comprisesa moving mechanism 48. The moving mechanism 48 includes a movementactuator 48A. Examples of the movement actuator 48A include a voice coilmotor and/or a piezo actuator. The movement actuator 48A is connected tothe control device 30, and the control device 30 controls the movementactuator 48A. The movement actuator 48A generates power under thecontrol of the control device 30. The moving mechanism 48 moves themagnetic head 28 in the width direction of the magnetic tape MT byreceiving the power generated by the movement actuator 48A.

The magnetic tape drive 14 comprises an inclination mechanism 49. Theinclination mechanism 49 includes an inclination actuator 49A. Examplesof the inclination actuator 49A include a voice coil motor and/or apiezo actuator. The inclination actuator 49A is connected to the controldevice 30, and the control device 30 controls the inclination actuator49A. The inclination actuator 49A generates power under the control ofthe control device 30. The inclination mechanism 49 inclines themagnetic head 28 to a longitudinal direction LD side of the magnetictape MT with respect to a width direction WD by receiving the powergenerated by the inclination actuator 49A (see FIG. 8 ). That is, themagnetic head 28 is skewed on the magnetic tape MT under the control ofthe control device 30.

Here, as a comparative example with respect to the magnetic tape MT, acase in which a known magnetic tape MT0 in the related art is usedinstead of the magnetic tape MT will be described with reference toFIGS. 6 to 8 . It should be noted that, in a case in which the magnetictape MT0 and the magnetic tape MT are compared, there is a difference inthat the servo pattern 52 (see FIG. 6 ) is applied to the magnetic tapeMT0, whereas the servo pattern 58 (FIG. 9 ) is applied to the magnetictape MT.

As an example, as shown in FIG. 6 , on the front surface 31 of themagnetic tape MT0, servo bands SB1, SB2, and SB3 are data bands DB1 andDB2 are formed. It should be noted that, in the following, forconvenience of description, in a case in which the distinction is notspecifically needed, the servo bands SB1 to SB3 are referred to as aservo band SB, and the data bands DB1 and DB2 are referred to as a databand DB.

The servo bands SB1 to SB3 and the data bands DB1 and DB2 are formedalong the longitudinal direction LD (that is, a total length direction)of the magnetic tape MT0. Here, the total length direction of themagnetic tape MT0 refers to the traveling direction of the magnetic tapeMT0, in other words. The traveling direction of the magnetic tape MT0 isdefined in two directions of the forward direction which is a directionin which the magnetic tape MT0 travels from the sending reel 22 side tothe winding reel 38 side (hereinafter, also simply referred to as“forward direction”), and the backward direction which is a direction inwhich the magnetic tape MT0 travels from the winding reel 38 side to thesending reel 22 side (hereinafter, also simply referred to as “backwarddirection”).

The servo bands SB1 to SB3 are arranged at positions spaced in the widthdirection WD of the magnetic tape MT0 (hereinafter, also simply referredto as “width direction WD”). For example, the servo bands SB1 to SB3 arearranged at equal intervals along the width direction WD. It should benoted that, in the present embodiment, “equal interval” refers to theequal interval in the sense of including an error generally allowed inthe technical field to which the technology of the present disclosurebelongs, which is the error to the extent that it does not contradictthe purpose of the technology of the present disclosure, in addition tothe exact equal interval.

The data band DB1 is disposed between the servo band SB1 and the servoband SB2, and the data band DB2 is disposed between a servo band SB2 anda servo band SB3. That is, the servo bands SB and the data bands DB arearranged alternately along the width direction WD.

It should be noted that, in the example shown in FIG. 6 , forconvenience of description, three servo bands SB and two data bands DBare shown, but these are merely examples, and two servo bands SB and onedata band DB may be used, and the technology of the present disclosureis established even in a case in which four or more servo bands SB andthree or more data bands DB are used.

A plurality of servo patterns 52 are recorded in the servo band SB alongthe longitudinal direction of the magnetic tape MT0. The servo patterns52 are classified into a servo pattern 52A and a servo pattern 52B. Theplurality of servo patterns 52 are disposed at regular intervals alongthe longitudinal direction of the magnetic tape MT0. It should be notedthat, in the present embodiment, “regular” refers to the regularity inthe sense of including an error generally allowed in the technical fieldto which the technology of the present disclosure belongs, which is theerror to the extent that it does not contradict the purpose of thetechnology of the present disclosure, in addition to the exactregularity.

The servo band SB is divided by a plurality of frames 50 along thelongitudinal direction of the magnetic tape MT0. The frame 50 is definedby one set of servo patterns 52. In the example shown in FIG. 6 , theservo patterns 52A and 52B are shown as an example of the set of servopatterns 52. The servo patterns 52A and 52B are adjacent to each otheralong the longitudinal direction of the magnetic tape MT0, and the servopattern 52A is positioned on the upstream side in the forward directionin the frame 50, and the servo pattern 52B is positioned on thedownstream side in the forward direction.

The servo pattern 52 consists of a linear magnetization region pair 54.The linear magnetization region pair 54 is classified into a linearmagnetization region pair 54A and a linear magnetization region pair54B.

The servo pattern 52A consists of the linear magnetization region pair54A. In the example shown in FIG. 6 , linear magnetization regions 54A1and 54A2 are shown as an example of the linear magnetization region pair54A. Each of the linear magnetization regions 54A1 and 54A2 is alinearly magnetized region.

The linear magnetization regions 54A1 and 54A2 are inclined in oppositedirections with respect to an imaginary straight line C1 which is animaginary straight line along the width direction WD. In the exampleshown in FIG. 6 , the linear magnetization regions 54A1 and 54A2 areinclined line-symmetrically with respect to the imaginary straight lineC1. More specifically, the linear magnetization regions 54A1 and 54A2are formed in a state of being not parallel to each other and beinginclined at a predetermined angle (for example, 5 degrees) in oppositedirections on the longitudinal direction side of the magnetic tape MT0with the imaginary straight line C1 as the symmetry axis. In the presentembodiment, the imaginary straight line C1 is an example of a “firstimaginary straight line” according to the technology of the presentdisclosure.

The linear magnetization region 54A1 is a set of magnetization straightlines 54A1 a, which are five magnetized straight lines. The linearmagnetization region 54A2 is a set of magnetization straight lines 54A2a, which are five magnetized straight lines.

The servo pattern 52B consists of the linear magnetization region pair54B. In the example shown in FIG. 6 , linear magnetization regions 54B1and 54B2 are shown as an example of the linear magnetization region pair54B. Each of the linear magnetization regions 54B1 and 54B2 is alinearly magnetized region.

The linear magnetization regions 54B1 and 54B2 are inclined in oppositedirections with respect to an imaginary straight line C2 which is animaginary straight line along the width direction WD. In the exampleshown in FIG. 6 , the linear magnetization regions 54B1 and 54B2 areinclined line-symmetrically with respect to the imaginary straight lineC2. More specifically, the linear magnetization regions 54B1 and 54B2are formed in a state of being not parallel to each other and beinginclined at a predetermined angle (for example, 5 degrees) in oppositedirections on the longitudinal direction side of the magnetic tape MT0with the imaginary straight line C2 as the symmetry axis. In the presentembodiment, the imaginary straight line C2 is an example of a “firstimaginary straight line” according to the technology of the presentdisclosure.

The linear magnetization region 54B1 is a set of magnetization straightlines 54B1 a, which are four magnetized straight lines. The linearmagnetization region 54B2 is a set of magnetization straight lines 54B2a, which are four magnetized straight lines.

The magnetic head 28 is disposed on the front surface 31 side of themagnetic tape MT0 configured as described above. The holder 44 is formedin a rectangular parallelepiped shape, and is disposed to cross thefront surface 31 of the magnetic tape MT0 along the width direction WD.The plurality of magnetic elements of the magnetic element unit 42 arearranged in a straight line along the longitudinal direction of theholder 44. The magnetic element unit 42 has a pair of servo readingelements SR and a plurality of data read/write elements DRW as theplurality of magnetic elements. A length of the holder 44 in thelongitudinal direction is sufficiently long with respect to the width ofthe magnetic tape MT0. For example, the length of the holder 44 in thelongitudinal direction is set to a length exceeding the width of themagnetic tape MT0 even in a case in which the magnetic element unit 42is disposed at any position on the magnetic tape MT.

The pair of servo reading elements SR consists of servo reading elementsSR1 and SR2. The servo reading element SR1 is disposed at one end of themagnetic element unit 42, and the servo reading element SR2 is disposedat the other end of the magnetic element unit 42. In the example shownin FIG. 6 , the servo reading element SR1 is provided at a positioncorresponding to the servo band SB2, and the servo reading element SR2is provided at a position corresponding to the servo band SB3.

The plurality of data read/write elements DRW are disposed in a straightline between the servo reading element SR1 and the servo reading elementSR2. The plurality of data read/write elements DRW are disposed atintervals along the longitudinal direction of the magnetic head 28 (forexample, are disposed at equal intervals along the longitudinaldirection of the magnetic head 28). In the example shown in FIG. 6 , theplurality of data read/write elements DRW are provided at positionscorresponding to the data band DB2.

The control device 30 acquires a servo signal which is a result ofreading the servo pattern 52 by the servo reading element SR, andperforms a servo control in response to the acquired servo signal. Here,the servo control refers to a control of moving the magnetic head 28 inthe width direction WD of the magnetic tape MT0 by operating the movingmechanism 48 in accordance with the servo pattern 52 read by the servoreading element SR.

By performing the servo control, the plurality of data read/writeelements DRW are positioned on a designated region in the data band DB,and perform the magnetic processing on the designated region in the databand DB. In the example shown in FIG. 6 , the plurality of dataread/write elements DRW perform the magnetic processing on thedesignated region in the data band DB2.

In addition, in a case in which the data band DB of which the data is tobe read by the magnetic element unit 42 is changed (in the example shownin FIG. 6 , the data band DB of which the data is to be read by themagnetic element unit 42 is changed from the data band DB2 to the databand DB1), the moving mechanism 48 moves, under the control of thecontrol device 30, the magnetic head 28 in the width direction WD tochange the position of the pair of servo reading elements SR. That is,by moving the magnetic head 28 in the width direction WD, the movingmechanism 48 moves the servo reading element SR1 to a positioncorresponding to the servo band SB1 and moves the servo reading elementSR2 to the position corresponding to the servo band SB2. As a result,the positions of the plurality of data read/write elements DRW arechanged from the data band DB2 to the data band DB1, and the pluralityof data read/write elements DRW perform the magnetic processing on thedata band DB1.

By the way, in recent years, research on a technology of reducing theinfluence of transverse dimensional stability (TDS) has been advanced.It has been known that the TDS is affected by a temperature, humidity, apressure at which the magnetic tape is wound around the reel, temporaldeterioration, or the like, the TDS is increased in a case in which nomeasures are taken, and off-track (that is, misregistration of the dataread/write element DRW with respect to the track in the data band DB)occurs in a scene in which the magnetic processing is performed on thedata band DB.

In the example shown in FIG. 7 , an aspect is shown in which the widthof the magnetic tape MT0 contracts with the elapse of time. In thiscase, the off-track occurs. In some cases, the width of the magnetictape MT0 expands, and the off-track occurs in this case as well. Thatis, in a case in which the width of the magnetic tape MT0 contracts orexpands with the elapse of time, the position of the servo readingelement SR with respect to the servo pattern 52 diverges from apredetermined position (for example, the center position of each of thelinear magnetization regions 54A1, 54A2, 54B1, and 54B2) determined bydesign in the width direction WD. In a case in which the position of theservo reading element SR with respect to the servo pattern 52 divergesfrom the predetermined position determined by the design in the widthdirection WD, the accuracy of the servo control is deteriorated, and theposition of the track in the data band DB and the position of the dataread/write element DRW deviate from each other. Then, an originallyplanned track will not be subjected to the magnetic processing.

As a method of reducing the influence of the TDS, as shown in FIG. 8 asshown in an example, a method of holding the position of the servoreading element SR with respect to the servo pattern 52 at thepredetermined position determined by design by skewing the magnetic head28 on the magnetic tape MT0 is known.

The magnetic head 28 comprises a rotation axis RA. The rotation axis RAis provided at a position corresponding to a center portion of themagnetic element unit 42 provided in the magnetic head 28 in a planview. The magnetic head 28 is rotatably held by the inclinationmechanism 49 via the rotation axis RA. An imaginary straight line C3which is an imaginary center line is provided in the magnetic head 28.The imaginary straight line C3 is a straight line that passes throughthe rotation axis RA and extends in the longitudinal direction of themagnetic head 28 in a plan view (that is, the direction in which theplurality of data read/write elements DRW are arranged). The magnetichead 28 is held by the inclination mechanism 49 to have a posture inwhich the imaginary straight line C3 is inclined to the longitudinaldirection side of the magnetic tape MT0 with respect to an imaginarystraight line C4 which is an imaginary straight line along the widthdirection WD. In the example shown in FIG. 8 , the magnetic head 28 isheld by the inclination mechanism 49 in a posture in which the imaginarystraight line C3 is inclined toward the sending reel 22 side withrespect to the imaginary straight line C4 (that is, a posture inclinedcounterclockwise as viewed from a paper surface side of FIG. 8 ). In thepresent embodiment, the imaginary straight line C3 is an example of a“second imaginary straight line” and a “third imaginary straight line”according to the technology of the present disclosure.

The inclination mechanism 49 receives the power from the inclinationactuator 49A (see FIG. 5 ) to rotate the magnetic head 28 around therotation axis RA on the front surface 31 of the magnetic tape MT0. Theinclination mechanism 49 rotates, under the control of the controldevice 30, the magnetic head 28 around the rotation axis RA on the frontsurface 31 of the magnetic tape MT0 to change the direction of theinclination of the imaginary straight line C3 with respect to theimaginary straight line C4 (that is, azimuth) and the inclined angle.

By changing the direction of the inclination of the imaginary straightline C3 with respect to the imaginary straight line C4 and the inclinedangle in accordance with the temperature, the humidity, the pressure atwhich the magnetic tape MT0 is wound around the reel, the temporaldeterioration, and the like, or expansion and contraction of themagnetic tape MT in the width direction WD due to these, the position ofthe servo reading element SR with respect to the servo pattern 52 isheld at the predetermined position determined in design.

By the way, the servo reading element SR is formed in a straight linealong the imaginary straight line C3. Therefore, in a case in which theservo pattern 52A is read by the servo reading element SR, in the linearmagnetization region pair 54A, an angle formed by the linearmagnetization region 54A1 and the servo reading element SR and an angleformed by the linear magnetization region 54A2 and the servo readingelement SR are different. In a case in which the angles are different inthis way, a variation due to an azimuth loss (for example, variation insignal level and waveform distortion) occurs between the servo signalderived from the linear magnetization region 54A1 (that is, the servosignal obtained by reading the linear magnetization region 54A1 by theservo reading element SR) and the servo signal derived from the linearmagnetization region 54A2 (that is, the servo signal obtained by readingthe linear magnetization region 54A2 by the servo reading element SR).In the example shown in FIG. 8 , since the angle formed by the servoreading element SR and the linear magnetization region 54A1 is largerthan the angle formed by the servo reading element SR and the linearmagnetization region 54A2, the output of the servo signal is small, andthe waveform also spreads, so that the variation occurs in the servosignal read by the servo reading element SR across the servo band SB ina state in which the magnetic tape MT travels. In addition, also in acase in which the servo pattern 52B is read by the servo reading elementSR, the variation due to the azimuth loss occurs between the servosignal derived from the linear magnetization region 54B1 and the servosignal derived from the linear magnetization region 54B2. Such avariation in the servo signal can contribute to a decrease in theaccuracy of the servo control.

For example, as another example of the conventionally known servopattern 52A, an aspect can be considered in which the linearmagnetization region 54A1 is parallel to the imaginary straight line C1and the linear magnetization region 54A2 is inclined with respect to theimaginary straight line C1 (i.e., only the linear magnetization region54A2 is inclined). In such a conventionally known aspect, in a case inwhich the servo pattern 52A is read by the servo reading element SR, inthe linear magnetization region pair 54A, an angle formed by the linearmagnetization region 54A1 and the servo reading element SR and an angleformed by the linear magnetization region 54A2 and the servo readingelement SR are different. In a case in which the angles are different inthis way, a variation due to an azimuth loss occurs between the servosignal derived from the linear magnetization region 54A1 and the servosignal derived from the linear magnetization region 54A2. Such avariation in the servo signal can contribute to a decrease in theaccuracy of the servo control.

Therefore, in view of such circumstances, in the present embodiment, asshown in FIG. 9 , the magnetic tape MT is adopted as an example. Themagnetic tape MT is different from the magnetic tape MT0 in that a frame56 is provided instead of the frame 50. The frame 56 is defined by a setof servo patterns 58. A plurality of servo patterns 58 are recorded inthe servo band SB along the longitudinal direction LD. The plurality ofservo patterns 58 are disposed at regular intervals along thelongitudinal direction LD, similarly to the plurality of servo patterns52 recorded in the magnetic tape MT0.

In the example shown in FIG. 9 , servo patterns 58A and 58B are shown asan example of the set of servo patterns 58 included in the frame 56. Theservo patterns 58A and 58B are adjacent to each other along thelongitudinal direction LD, and the servo pattern 58A is positioned onthe upstream side in the forward direction and the servo pattern 58B ispositioned on the downstream side in the forward direction in the frame56.

The servo pattern 58 consists of a linear magnetization region pair 60.The linear magnetization region pair 60 is classified into a linearmagnetization region pair 60A and a linear magnetization region pair60B.

The servo pattern 58A consists of the linear magnetization region pair60A. In the example shown in FIG. 9 , linear magnetization regions 60A1and 60A2 are shown as an example of the linear magnetization region pair60A. Each of the linear magnetization regions 60A1 and 60A2 is alinearly magnetized region.

The linear magnetization regions 60A1 and 60A2 are inclined in oppositedirections with respect to the imaginary straight line C1. In otherwords, the linear magnetization region 60A1 is inclined in one direction(for example, in the clockwise direction as viewed from the papersurface side of FIG. 9 ) with respect to the imaginary straight line C1.On the other hand, the linear magnetization region 60A2 is inclined inanother direction (for example, in the counter clockwise direction asviewed from the paper surface side of FIG. 9 ) with respect to theimaginary straight line C1. The linear magnetization regions 60A1 and60A2 are not parallel to each other and are inclined at different angleswith respect to the imaginary straight line C1. The linear magnetizationregion 60A1 has a steeper inclined angle with respect to the imaginarystraight line C1 than the linear magnetization region 60A2. Here,“steep” means that, for example, an angle of the linear magnetizationregion 60A1 with respect to the imaginary straight line C1 is smallerthan an angle of the linear magnetization region 60A2 with respect tothe imaginary straight line C1. In addition, a total length of thelinear magnetization region 60A1 is shorter than a total length of thelinear magnetization region 60A2.

In the servo pattern 58A, a plurality of magnetization straight lines60A1 a are included in the linear magnetization region 60A1, and aplurality of magnetization straight lines 60A2 a are included in thelinear magnetization region 60A2. The number of the magnetizationstraight lines 60A1 a included in the linear magnetization region 60A1is the same as the number of the magnetization straight lines 60A2 aincluded in the linear magnetization region 60A2.

The linear magnetization region 60A1 is a set of magnetization straightlines 60A1 a, which are five magnetized straight lines, and the linearmagnetization region 60A2 is a set of magnetization straight lines 60A2a, which are five magnetized straight lines. In the servo band SB, thepositions of both ends of the linear magnetization region 60A1 (that is,the positions of both ends of each of the five magnetization straightlines 60A1 a) and the positions of both ends of the linear magnetizationregion 60A2 (that is, the positions of both ends of each of the fivemagnetization straight lines 60A2 a) are aligned in the width directionWD. It should be noted that, here, the example has been described inwhich the positions of both ends of each of the five magnetizationstraight lines 60A1 a and the positions of both ends of each of the fivemagnetization straight lines 60A2 a are aligned, but this is merely anexample, and the positions of both ends of one or more magnetizationstraight lines 60A1 a among the five magnetization straight lines 60A1 aand the positions of both ends of one or more magnetization straightlines 60A2 a among of the five magnetization straight lines 60A2 a needonly be aligned. In addition, in the present embodiment, the concept of“aligned” also includes meaning of “aligned” including an errorgenerally allowed in the technical field to which the technology of thepresent disclosure belongs, which is the error to the extent that itdoes not contradict the purpose of the technology of the presentdisclosure, in addition to the meaning of being exactly aligned.

The servo pattern 58B consists of the linear magnetization region pair60B. In the example shown in FIG. 9 , linear magnetization regions 60B1and 60B2 are shown as an example of the linear magnetization region pair60B. Each of the linear magnetization regions 60B1 and 60B2 is alinearly magnetized region.

The linear magnetization regions 60B1 and 60B2 are inclined in oppositedirections with respect to the imaginary straight line C2. In otherwords, the linear magnetization region 60B1 is inclined in one direction(for example, in the clockwise direction as viewed from the papersurface side of FIG. 9 ) with respect to the imaginary straight line C1.On the other hand, the linear magnetization region 60B2 is inclined inanother direction (for example, in the counter clockwise direction asviewed from the paper surface side of FIG. 9 ) with respect to theimaginary straight line C1. The linear magnetization regions 60B1 and60B2 are not parallel to each other and are inclined at different angleswith respect to the imaginary straight line C2. The linear magnetizationregion 60B1 has a steeper inclined angle with respect to the imaginarystraight line C2 than the linear magnetization region 60B2. Here,“steep” means that, for example, an angle of the linear magnetizationregion 60B1 with respect to the imaginary straight line C2 is smallerthan an angle of the linear magnetization region 60B2 with respect tothe imaginary straight line C2. In addition, a total length of thelinear magnetization region 60B1 is shorter than a total length of thelinear magnetization region 60B2.

In the servo pattern 58B, a plurality of magnetization straight lines60B1 a are included in the linear magnetization region 60B1, and aplurality of magnetization straight lines 60B2 a are included in thelinear magnetization region 60B2. The number of the magnetizationstraight lines 60B1 a included in the linear magnetization region 60B1is the same as the number of the magnetization straight lines 60B2 aincluded in the linear magnetization region 60B2.

The total number of the magnetization straight lines 60B1 a and 60B2 aincluded in the servo pattern 58B is different from the total number ofthe magnetization straight lines 60A1 a and 60A2 a included in the servopattern 58A. In the example shown in FIG. 9 , the total number of themagnetization straight lines 60A1 a and 60A2 a included in the servopattern 58A is ten, whereas the total number of the magnetizationstraight lines 60B1 a and 60B2 a included in the servo pattern 58B iseight.

The linear magnetization region 60B1 is a set of magnetization straightlines 60B1 a, which are four magnetized straight lines, and the linearmagnetization region 60B2 is a set of magnetization straight lines 60B2a, which are four magnetized straight lines. In the servo band SB, thepositions of both ends of the linear magnetization region 60B1 (that is,the positions of both ends of each of the four magnetization straightlines 60B1 a) and the positions of both ends of the linear magnetizationregion 60B2 (that is, the positions of both ends of each of the fourmagnetization straight lines 60B2 a) are aligned in the width directionWD.

It should be noted that, here, the example has been described in whichthe positions of both ends of each of the four magnetization straightlines 60B1 a and the positions of both ends of each of the fourmagnetization straight lines 60B2 a are aligned, but this is merely anexample, and the positions of both ends of one or more magnetizationstraight lines 60B1 a among the four magnetization straight lines 60B 1a and the positions of both ends of one or more magnetization straightlines 60B2 a among of the four magnetization straight lines 60B2 a needonly be aligned.

In addition, here, the set of magnetization straight lines 60A1 a, whichare five magnetized straight lines, is described as an example of thelinear magnetization region 60A1, the set of magnetization straightlines 60A2 a, which are five magnetized straight lines, is described asan example of the linear magnetization region 60A2, the set ofmagnetization straight lines 60B 1 a, which are four magnetized straightlines, is described as an example of the linear magnetization region60B1, and the set of magnetization straight lines 60B2 a, which are fourmagnetized straight lines, is described as an example of the linearmagnetization region 60B2, but the technology of the present disclosureis not limited thereto. For example, the linear magnetization region60A1 need only have the number of the magnetization straight lines 60A1a that contribute to specifying the position of the magnetic head 28 onthe magnetic tape MT, the linear magnetization region 60A2 need onlyhave the number of the magnetization straight lines 60A2 a thatcontribute to specifying the position of the magnetic head 28 on themagnetic tape MT, the linear magnetization region 60B1 need only havethe number of the magnetization straight lines 60B1 a that contribute tospecifying the position of the magnetic head 28 on the magnetic tape MT,and the linear magnetization region 60B2 need only have the number ofthe magnetization straight lines 60B2 a that contribute to specifyingthe position of the magnetic head 28 on the magnetic tape MT.

Here, the geometrical characteristic of the linear magnetization regionpair 60A on the magnetic tape MT will be described with reference toFIG. 10 . Note that, in present embodiment, the geometric characteristicrefers to generally recognized geometric characteristic such as length,shape, orientation, position and/or like.

As an example, as shown in FIG. 10 the geometrical characteristic of thelinear magnetization region pair 60A on the magnetic tape MT can beexpressed by using an imaginary linear region pair 62. The imaginarylinear region pair 62 consists of the imaginary linear region 62A and animaginary linear region 62B.

The imaginary linear region pair 62 is an imaginary linear magnetizationregion pair having the same geometrical characteristic as the linearmagnetization region pair 54A shown in FIG. 6 . The imaginary linearregion pair 62 is an imaginary magnetization region used for conveniencefor describing the geometrical characteristic of the linearmagnetization region pair 60A on the magnetic tape MT, and is not anactually present magnetization region.

The imaginary linear region 62A has the same geometrical characteristicas the linear magnetization region 54A1 shown in FIG. 6 , and consistsof five imaginary straight lines 62A1 corresponding to the fivemagnetization straight lines 54A1 a shown in FIG. 6 . The imaginarylinear region 62B has the same geometrical characteristic as the linearmagnetization region 54B1 shown in FIG. 6 , and consists of fiveimaginary straight lines 62B1 corresponding to the five magnetizationstraight lines 54A2 a shown in FIG. 6 .

A center O1 is provided in the imaginary linear region pair 62. Forexample, the center O1 is a center of a line segment L0 connecting acenter of the straight line 62A1 positioned on the most upstream side ofthe five straight lines 62A1 in the forward direction and a center ofthe straight line 62B1 positioned on the most downstream side of thefive straight lines 62B1 in the forward direction.

Since the imaginary linear region pair 62 has the same geometricalcharacteristic as the linear magnetization region pair 54A shown in FIG.6 , the imaginary linear region 62A and the imaginary linear region 62Bare inclined line-symmetrically with respect to the imaginary straightline C1. Here, a case will be considered in which reading by the servoreading element SR is performed tentatively with respect to theimaginary linear region pair 62 in a case in which an entirety of theimaginary linear region pair 62 is inclined with respect to theimaginary straight line C1 by inclining the symmetry axis SA1 of theimaginary linear regions 62A and 62B at an angle a (for example, 10degrees) with respect to the imaginary straight line C1 with the centerO1 as the rotation axis. In this case, in the imaginary linear regionpair 62, in the width direction WD, a portion is generated in which theimaginary linear region 62A is read but the imaginary linear region 62Bis not read or the imaginary linear region 62A is not read is read butthe imaginary linear region 62B. That is, in each of the imaginarylinear regions 62A and 62B, in a case in which reading by the servoreading element SR is performed, a shortage part and an unnecessary partis generated.

Therefore, by compensating for the shortage part and removing theunnecessary part, the positions of both ends of the imaginary linearregion 62A (that is, the positions of both ends of each of the fivestraight lines 62A1) and the positions of both ends of the imaginarylinear region 62B (that is, the positions of both ends of each of thefive straight lines 62B1) are aligned in the width direction WD.

The geometrical characteristic of the imaginary linear region pair 62(that is, the geometrical characteristic of the imaginary servo pattern)obtained as described above corresponds to the geometricalcharacteristic of the actual servo pattern 58A. That is, the linearmagnetization region pair 60A having the geometrical characteristiccorresponding to the geometrical characteristic of the imaginary linearregion pair 62 obtained by aligning the positions of both ends of theimaginary linear region 62A and the positions of both ends of theimaginary linear region 62B in the width direction WD is recorded in theservo band SB.

It should be noted that the linear magnetization region pair 60B isdifferent from the linear magnetization region pair 60A only in that thefour magnetization straight lines 60B 1 a are provided instead of thefive magnetization straight lines 60A1 a and the four magnetizationstraight lines 60B2 a are provided instead of the five magnetizationstraight lines 60A2 a. Therefore, the linear magnetization region pair60B having the geometrical characteristic corresponding to thegeometrical characteristic of the imaginary linear region pair (notshown) obtained by aligning the positions of both ends of each of thefour straight lines 62A1 and the positions of both ends of each of thefour straight lines 62B1 in the width direction WD is recorded in theservo band SB.

As an example, as shown in FIG. 11 , the plurality of servo bands SB areformed on the magnetic tape MT in the width direction WD, and the frames56 having a correspondence relationship between the servo bands SBdeviate from each other at predetermined intervals in the longitudinaldirection LD, between the servo bands SB adjacent to each other in thewidth direction WD. This means that the servo patterns 58 having acorrespondence relationship between the servo bands SB deviate from eachother at the predetermined interval in the longitudinal direction LDbetween the servo bands SB adjacent to each other in the width directionWD.

The predetermined interval is defined based on an angle α, a pitchbetween the servo bands SB adjacent to each other in the width directionWD (hereinafter, also referred to as “servo band pitch”), and a framelength. In the example shown in FIG. 11 , the angle α is exaggerated inorder to make it easier to visually grasp the angle α, but in reality,the angle α is, for example, about 15 degrees. The angle α is an angleformed by the frames 56 having no correspondence relationship betweenthe servo bands SB adjacent to each other in the width direction WD andthe imaginary straight line C1. In the example shown in FIG. 11 , as anexample of the angle α, an angle formed by an interval (in the exampleshown in FIG. 11 , a line segment L1) between one frame 56 of a pair offrames 56 having the correspondence relationship between the servo bandsSB adjacent to each other in the width direction WD (in the exampleshown in FIG. 11 , one frame 56 of the servo band SB3) and the frame 56adjacent to the other frame 56 of the pair of frames 56 (in the exampleshown in FIG. 11 , the frame 56 having the correspondence relationshipwith one frame 56 of the servo band SB3 among the plurality of frames 56in the servo band SB2), and the imaginary straight line C1 is shown. Inthis case, the frame length refers to the total length of the frame 56with respect to the longitudinal direction LD. The predeterminedinterval is defined by Expression (1). It should be noted that Mod (AB)means a remainder generated in a case in which “A” is divided by “B”.

(Predetermined interval)=Mod{(Servo band pitch×tan α)/(Framelength)}  (1)

It should be noted that, in the example shown in FIG. 11 , the angleformed by the interval between one frame 56 of the pair of frames 56having the correspondence relationship between the servo bands SBadjacent to each other in the width direction WD (hereinafter, alsoreferred to as “first frame”) and the frame 56 adjacent to the otherframe 56 of the pair of frames 56 (hereinafter, also referred to as“second frame”), and the imaginary straight line C1 has been describedas the angle α, but the technology of the present disclosure is notlimited to this. For example, as the angle α, an angle formed by aninterval between the first frame and the frame 56 away from the secondframe by two or more frames (hereinafter, also referred to as “thirdframe”) in the same servo band SB as the second frame, and the imaginarystraight line C1 may be used. In this case, the “frame length” used inExpression (1) is the pitch between the second frame and the third framein the longitudinal direction LD (for example, a distance from thedistal end of the second frame to the distal end of the third frame).

As an example, as shown in FIG. 12 , in a case in which the servopattern 58A (that is, the linear magnetization region pair 60A) is readby the servo reading element SR in a state in which the direction of theimaginary straight line C1 and the direction of the imaginary straightline C3 match (that is, a state in which the longitudinal direction ofthe magnetic head 28 and the width direction WD match), the variationdue to the azimuth loss occurs between the servo signal derived from thelinear magnetization region 60A1 and the servo signal derived from thelinear magnetization region 60A2. In addition, also in a case in whichthe servo pattern 58B (that is, the linear magnetization region pair60B) is read by the servo reading element SR in a state in which thedirection of the imaginary straight line C1 and the direction of theimaginary straight line C3 match (that is, a state in which thelongitudinal direction of the magnetic head 28 and the width directionWD match), a similar phenomenon occurs.

Therefore, as an example, as shown in FIG. 13 , the inclinationmechanism 49 (see FIG. 8 ) skews the magnetic head 28 on the magnetictape MT around the rotation axis RA such that the imaginary straightline C3 is inclined with respect to the imaginary straight line C1 tothe upstream side in the forward direction at an angle β (that is, theangle β counterclockwise as viewed from the paper surface side of FIG.13 ). As described above, since the magnetic head 28 is inclined to theupstream side in the forward direction at the angle β on the magnetictape MT, the variation due to the azimuth loss between the servo signalderived from the linear magnetization region 60A1 and the servo signalderived from the linear magnetization region 60A2 is smaller than thatin the example shown in FIG. 12 . In addition, also in a case in whichthe servo pattern 58B (that is, the linear magnetization region pair60B) is read by the servo reading element SR, similarly, the variationdue to the azimuth loss between the servo signal derived from the linearmagnetization region 60B1 and the servo signal derived from the linearmagnetization region 60B2 is small.

Here, the angle β is set to match, for example, the angle a (see FIG. 10), which is an angle at which the symmetrical axis SA1 (see FIG. 10 ) ofthe imaginary linear regions 62A and 62B (see FIG. 10 ) is rotatedrelative to the imaginary straight line C1 with the center O1 (see FIG.10 ) as the rotation axis. Note that, in the present embodiment, theterm “match” means, in addition to perfect match, match in a senseincluding errors that are generally acceptable in the art to which thetechnology of the present disclosure belongs and that are not contraryto the object of the technology of the present disclosure. The geometriccharacteristics of the imaginary linear regions 62A and 62B are the sameas the geometric characteristics of the linear magnetization regions60A1 and 60B1. Therefore, the linear magnetization regions 60A1 and 60B1are also inclined at the angle a with respect to the imaginary straightline C1. In such a case, when the magnetic head 28 is inclined at theangle β (i.e., the angle a) to the upstream side in the forwarddirection on the magnetic tape MT, the inclined angle of the magnetichead 28 and the inclined angle of the linear magnetization regions 60A1and 60A2 match. As a result, the variation due to azimuth loss betweenthe servo signal derived from the linear magnetization region 60A1 andthe servo signal derived from the linear magnetization region 60A2 isreduced. Similarly, when the servo pattern 58B (i.e., the linearmagnetization region pair 60B) is read by the servo reading element SR,the variation due to azimuth loss between the servo signal derived fromthe linear magnetization region 60B1 and the servo signal derived fromthe linear magnetization region 60B2 is reduced.

As an example, as shown in FIG. 14 , the control device 30 includes acontroller 30A and a position detection unit 30B. The position detectionunit 30B includes a first position detection unit 30B1 and a secondposition detection unit 30B2. The position detection unit 30B acquiresthe servo signal that is a result of reading the servo pattern 58 by theservo reading element SR, and detects the position of the magnetic head28 on the magnetic tape MT based on the acquired servo signal.

The servo signal is classified into a first servo signal and a secondservo signal. The first servo signal is a servo signal that is theresult of reading the servo pattern 58 by the servo reading element SR1,and the second servo signal is the servo signal that is a result ofreading the servo pattern 58 by the servo reading element SR2.

The first position detection unit 30B1 acquires the first servo signal,and the second position detection unit 30B2 acquires the second servosignal. In the example shown in FIG. 14 , the first position detectionunit 30B1 acquires the first servo signal obtained by reading the servopattern 58 in the servo band SB2 by the servo reading element SR1, andthe second position detection unit 30B2 acquires the second servo signalobtained by reading the servo pattern 58 in the servo band SB3 by theservo reading element SR2. The first position detection unit 30B1detects the position of the servo reading element SR1 with respect tothe servo band SB2 based on the first servo signal, and the secondposition detection unit 30B2 detects the position of the servo readingelement SR2 with respect to the servo band SB3 based on the second servosignal.

The controller 30A performs various controls based on a positiondetection result by the first position detection unit 30B1 (that is, aresult of detecting the position by the first position detection unit30B1) and a position detection result by the second position detectionunit 30B2 (that is, a result of detecting the position by the secondposition detection unit 30B2). Here, the various controls refer to, forexample, the servo control, a skew angle control, and/or a tensioncontrol. The tension control refers to a control of the tension appliedto the magnetic tape MT (for example, the tension for reducing theinfluence of the TDS).

As an example, as shown in FIG. 15 , the position detection unit 30Bdetects the servo signal, which is the result of reading the servopattern 58 from the magnetic tape MT by the servo reading element SR, byusing an autocorrelation coefficient.

An ideal waveform signal 66 is stored in the storage 32. The idealwaveform signal 66 is a signal indicating a single ideal waveformincluded in the servo signal (for example, an ideal signal which is aresult of reading one of an ideal magnetization straight lines includedin the servo pattern 58 by the servo reading element SR). The idealwaveform signal 66 can be said to be a sample signal compared with theservo signal. It should be noted that, here, the form example has beendescribed in which the ideal waveform signal 66 is stored in the storage32, but this is merely an example. For example, the ideal waveformsignal 66 may be stored in the cartridge memory 24 instead of thestorage 32 or together with the storage 32. In addition, the idealwaveform signal 66 may be recorded in a BOT region (not shown) providedat the beginning of the magnetic tape MT and/or in an EOT region (notshown) provided at the end of the magnetic tape MT.

The autocorrelation coefficient used by the position detection unit 30Bis a coefficient indicating a degree of correlation between the servosignal and the ideal waveform signal 66. The position detection unit 30Bacquires the ideal waveform signal 66 from the storage 32 to compare theacquired ideal waveform signal 66 with the servo signal. Moreover, theposition detection unit 30B calculates the autocorrelation coefficientbased on the comparison result. The position detection unit 30B detectsa position on the servo band SB at which the correlation between theservo signal and the ideal waveform signal 66 is high (for example, aposition at which the servo signal and the ideal waveform signal 66match) in accordance with the autocorrelation coefficient.

Detecting the position of the servo reading element SR with respect tothe servo band SB is performed, for example, as follows. Theautocorrelation coefficient makes it possible to detect an intervalbetween the servo patterns 58A and 58B in the longitudinal direction LD.For example, in a case in which the servo reading element SR ispositioned on the upper side of the servo pattern 58 (that is, the upperside of the front view of the paper surface in FIG. 14 ), the intervalbetween the linear magnetization region 60A1 and the linearmagnetization region 60A2 is narrow, and the interval between the linearmagnetization region 60B1 and the linear magnetization region 60B2 isalso narrow. In contrast, in a case in which the servo reading elementSR is positioned on the lower side of the servo pattern 58 (that is, thelower side of the front view of the paper surface in FIG. 14 ), theinterval between the linear magnetization region 60A1 and the linearmagnetization region 60A2 is wide, and the interval between the linearmagnetization region 60B1 and the linear magnetization region 60B2 isalso wide. As described above, the position detection unit 30B detectsthe position of the servo reading element SR with respect to the servoband SB by using the interval between the servo pattern 58A and theservo pattern 58B detected in accordance with the autocorrelationcoefficient. The controller 30A adjusts the position of the magnetichead 28 by operating the moving mechanism 48 based on the positiondetection result of the position detection unit 30B (that is, the resultof detecting the position by the position detection unit 30B). Inaddition, the controller 30A causes the magnetic element unit 42 toperform the magnetic processing on the data band DB of the magnetic tapeMT. That is, the controller 30A acquires a read signal (data read fromthe data band DB of the magnetic tape MT by the magnetic element unit42) from the magnetic element unit 42, or supplies a recording signal tothe magnetic element unit 42 to record the data in response to therecording signal in the data band DB of the magnetic tape MT.

In addition, in order to reduce the influence of the TDS, the controller30A calculates the servo band pitch from the position detection resultof the position detection unit 30B, and performs the tension control inaccordance with the calculated servo band pitch, or skews the magnetichead 28 on the magnetic tape MT. The tension control is realized byadjusting the rotation speed, rotation torque, and the like of each ofthe sending motor 36 and the winding motor 40. The skew of the magnetichead 28 is realized by operating the inclination mechanism 49.

Next, an example of a servo pattern recording step of recording theservo pattern 58 on the servo band SB of the magnetic tape MT and anexample of a winding step of winding the magnetic tape MT will bedescribed.

As an example, as shown in FIG. 16 , a servo writer SW is used in theservo pattern recording step. The servo writer SW comprises a sendingreel SW1, a winding reel SW2, a driving device SW3, a pulse signalgenerator SW4, a control device SW5, a plurality of guides SW6, atransport passage SW7, a servo pattern recording head WH, and averification head VH.

In the present embodiment, the servo writer SW is an example of a “servopattern recording device” and an “inspection device” according to thetechnology of the present disclosure. In addition, in the presentembodiment, the pulse signal generator SW4 is an example of a “pulsesignal generator” according to the technology of the present disclosure.In addition, in the present embodiment, the servo pattern recording headWH is an example of a “servo pattern recording head” according to thetechnology of the present disclosure. In addition, in the presentembodiment, the control device SW5 is an example of an “inspectionprocessor” according to the technology of the present disclosure.

The control device SW5 controls the entire servo writer SW. In thepresent embodiment, although the control device SW5 is realized by anASIC, the technology of the present disclosure is not limited to this.For example, the control device SW5 may be realized by an FPGA and/or aPLC. In addition, the control device SW5 may be realized by the computerincluding a CPU, a flash memory (for example, an EEPROM and/or an SSD),and a RAM. In addition, the control device 30 may be realized bycombining two or more of an ASIC, an FPGA, a PLC, and a computer. Thatis, the control device SW5 may be realized by a combination of ahardware configuration and a software configuration.

A pancake is set in the sending reel SW1. The pancake refers to alarge-diameter roll in which the magnetic tape MT cut into a productwidth from a wide web raw material before writing the servo pattern 58is wound around a hub.

The driving device SW3 has a motor (not shown) and a gear (not shown),and is mechanically connected to the sending reel SW1 and the windingreel SW2. In a case in which the magnetic tape MT is wound by thewinding reel SW2, the driving device SW3 generates power in accordancewith the command from the control device SW5, and transmits thegenerated power to the sending reel SW1 and the winding reel SW2 torotate the sending reel SW1 and the winding reel SW2. That is, thesending reel SW1 receives the power from the driving device SW3 and isrotated to send the magnetic tape MT to the predetermined transportpassage SW7. The winding reel SW2 receives the power from the drivingdevice SW3 and is rotated to wind the magnetic tape MT sent from thesending reel SW1. The rotation speed, the rotation torque, and the likeof the sending reel SW1 and the winding reel SW2 are adjusted inaccordance with a speed at which the magnetic tape MT is wound aroundthe winding reel SW2.

The plurality of guides SW6 and the servo pattern recording head WH aredisposed on the transport passage SW7. The servo pattern recording headWH is disposed on the front surface 31 side of the magnetic tape MTbetween the plurality of guides SW6. The magnetic tape MT sent from thesending reel SW1 to the transport passage SW7 is guided by the pluralityof guides SW6 and is wound by the winding reel SW2 via the servo patternrecording head WH.

The manufacturing process of the magnetic tape MT includes a pluralityof steps in addition to the servo pattern recording step. The pluralityof steps include an inspection step and a winding step.

For example, the inspection step is a step of inspecting the servo bandSB formed on the surface 31 of the magnetic tape MT by the servo patternrecording head WH. The inspection of the servo band SB refers to, forexample, a process of determining whether the servo pattern 58 recordedon the servo band SB is correct or not. The determination of whether theservo pattern 58 is correct or not refers to, for example, adetermination of whether the servo patterns 58A and 58B are recorded forpredetermined locations within the surface 31, without excessive orinsufficient magnetization lines 60A1 a, 60A2 a, 60B1 a and 60B2 a andwithin the tolerance (i.e., refers to a verification of the servopattern 58).

The inspection step is performed by using the control device SW5 and theverification head VH. The verification head VH is disposed on thedownstream side of the servo pattern recording head WH in the transportdirection of the magnetic tape MT. In addition, the verification head VHis provided with a plurality of servo reading elements (not shown) inthe same way as the magnetic head 28, and the plurality of servo bandsSB are read by the plurality of servo reading elements. Further, theverification head VH is skewed on the surface 31 of the magnetic tape MTin the same way as the magnetic head 28.

The verification head VH is connected to the control device SW5. Theverification head VH is disposed at a position directly facing the servoband SB as viewed from the surface 31 side of the magnetic tape MT(i.e., the back side of the verification head VH), reads the servopattern 58 recorded in the servo band SB, and outputs the read result(hereinafter referred to as “servo pattern reading result”) to thecontrol device SW5. The control device SW5 inspects the servo band SB(for example, determines whether the servo pattern 58 is correct or not)based on the servo pattern reading result (for example, the servosignal) input from the verification head VH. For example, the controldevice SW5 operates as the position detection unit 30B shown in FIG. 14to obtain a position detection result from the servo pattern readingresult, and uses the position detection result to determine whether theservo pattern 58 is correct or not to thereby inspect the servo band SB.

The control device SW5 outputs information indicating the result ofinspecting the servo band SB (for example, the result of determiningwhether the servo pattern 58 is correct or not) to a predeterminedoutput destination (for example, the storage 32 (see FIG. 3 ), the UIsystem device 34 (see FIG. 3 ), the external device 37 (see FIG. 3 )and/or the like).

For example, after the inspection step is finished, a winding step isperformed next. The winding step is a step of winding the magnetic tapeMT around the sending reel 22 (that is, the sending reel 22 (see FIGS. 2to 4 ) accommodated in the magnetic tape cartridge 12 (FIGS. 1 to 4 ))used for each of the plurality of magnetic tape cartridges 12 (see FIGS.1 to 4 ). In the winding step, a winding motor M is used. The windingmotor M is mechanically connected to the sending reel 22 via a gear andthe like. The winding motor M rotates the sending reel 22 by applying arotation force to the sending reel 22 under the control of the controldevice (not shown). The magnetic tape MT wound around the winding reelSW2 is wound around the sending reel 22 by the rotation of the sendingreel 22. In the winding step, a cutting device (not shown) is used. In acase in which a required amount of the magnetic tape MT is wound aroundthe sending reel 22 for each of the plurality of sending reels 22, themagnetic tape MT sent from the winding reel SW2 to the sending reel 22is cut by the cutting device.

The pulse signal generator SW4 generates the pulse signal under thecontrol of the control device SW5, and supplies the generated pulsesignal to the servo pattern recording head WH. In a state in which themagnetic tape MT travels on the transport passage SW7 at a regularspeed, the servo pattern recording head WH records the servo pattern 58in the servo band SB in response to the pulse signal supplied from thepulse signal generator SW4.

FIG. 17 shows an example of a configuration of the servo patternrecording head WH and an example of a configuration of the pulse signalgenerator SW4 in a case in which the servo pattern recording head WH isobserved from the front surface 31 side (that is, the rear surface sideof the servo pattern recording head WH) of the magnetic tape MT thattravels on the transport passage SW7 (see FIG. 16 ).

As an example, as shown in FIG. 17 , the servo pattern recording head WHhas a substrate WH1 and a plurality of head cores WH2. The substrate WH1is formed in a rectangular parallelepiped shape, and is disposed tocross the front surface 31 of the magnetic tape MT that travels on thetransport passage SW7 along the width direction WD. A front surface WH1Aof the substrate WH1 is a rectangle having a long side WH1Aa and a shortside WH1Ab. The longitudinal direction of the substrate WH1, that is,the orientation of the long side WH1Aa is aligned with a direction WD1corresponding to the width direction WD (for example, the same directionas the width direction WD). In addition, on the front surface 31, thesubstrate WH1 crosses the magnetic tape MT in a direction orthogonal tothe longitudinal direction LD. That is, the long side WH1Aa crosses thefront surface 31 of the magnetic tape MT from one end side to the otherend side of the width of the magnetic tape MT along the width directionWD.

The front surface WH1A has a sliding surface WH1Ax. The sliding surfaceWH1Ax is a surface overlapping the front surface 31 of the magnetic tapeMT in the front surface WH1A under a situation in which the substrateWH1 diagonally crosses the front surface 31 of the magnetic tape MTalong the width direction WD (for example, a dot-shaped hatching regionshown in FIG. 17 ), and slides against the magnetic tape MT in atraveling state. The width of the sliding surface WH1Ax shown in FIG. 17(that is, the length of the short side WH1Ab) is merely an example, andthe width of the sliding surface WH1Ax may be several times wider thanthat of the example shown in FIG. 17 .

The plurality of head cores WH2 are incorporated in the substrate WH1along the direction WD1. The direction in which the plurality of headcores WH2 are arranged matches the orientation of the long side WH1Aa.That is, positions of the plurality of head cores WH2 in thelongitudinal direction LD are aligned.

A gap pattern G is formed in the head core WH2. The gap pattern G isformed on the front surface WH1A (that is, the surface of the substrateWH1 that faces the front surface 31 of the magnetic tape MT). Inaddition, the gap pattern G consists of a pair of non-parallel straightline regions. The pair of non-parallel straight line regions refers to,for example, the straight line region having the same geometricalcharacteristic as the geometrical characteristic of the magnetizationstraight line 60A1 a positioned on the most upstream side in the forwarddirection among the five magnetization straight lines 60A1 a included inthe linear magnetization region 60A1 shown in FIG. 9 , and the straightline region having the same geometrical characteristic as thegeometrical characteristic of the magnetization straight line 60A2 apositioned on the most upstream side in the forward direction among thefive magnetization straight lines 60A2 a included in the linearmagnetization region 60A2 shown in FIG. 9 .

A plurality of gap patterns G are formed on the front surface WH1A alongthe direction WD1. The direction in which the plurality of gap patternsG are arranged in the front surface WH1A matches the orientation of thelong side WH1Aa. In other words, on the front surface WH1A, theplurality of gap patterns G are arranged in a straight line along thelong side WH1Aa. In addition, on the front surface WH1A, the positionsof the plurality of gap patterns G in the longitudinal direction LD arealigned. On the front surface WH1A, an interval between the gap patternsG adjacent to each other in the direction WD1 with respect to thedirection WD1 corresponds to the interval between the servo bands SB ofthe magnetic tape MT with respect to the width direction WD (that is,the servo band pitch).

A coil (not shown) is wound around the head core WH2, and the pulsesignal is supplied to the coil. The pulse signal supplied to the coil isthe pulse signal for the servo pattern 58A and the pulse signal for theservo pattern 58B.

In a case in which the pulse signal for the servo pattern 58A issupplied to the coil of the head core WH2 in a state in which the gappattern G faces the servo band SB of the magnetic tape MT that travelson the transport passage SW7, the magnetic field is applied to the servoband SB of the magnetic tape MT from the gap pattern Gin response to thepulse signal. As a result, the servo pattern 58A is recorded in theservo band SB. In addition, by supplying the pulse signal for the servopattern 58B to the coil of the head core WH2 in a state in which the gappattern G faces the servo band SB of the magnetic tape MT that travelson the transport passage SW7, the magnetic field is applied to the servoband SB of the magnetic tape MT from the gap pattern Gin response to thepulse signal. As a result, the servo pattern 58B is recorded in theservo band SB.

The pulse signal corresponding to each servo pattern 58 (that is, theservo pattern 58 for each frame 56 (see FIG. 9 )) is modulated. Bymodulating the pulse signal, various pieces of information are embeddedin the pulse signal. In this case, for example, by modulating the pulsesignal for the servo pattern 58A, it is possible to change, for eachservo pattern 58A, the interval between the third magnetization straightline 60A1 a and the second magnetization straight line 60A1 a among thefive magnetization straight lines 60A1 a (see FIG. 9 ) (hereinafter,also referred to as “first interval”), and the interval between thethird magnetization straight line 60A1 a and the fourth magnetizationstraight line 60A1 a (hereinafter, also referred to as “secondinterval”). By making the first interval and the second intervaldifferent for each servo pattern 58A, it is possible to embed theinformation of at least 1 bit in each servo pattern 58A. As a result, itis possible to embed various pieces of information by combining theplurality of servo patterns 58.

It should be noted that, in the pulse signal, information on theposition in the longitudinal direction LD, information for identifyingthe servo band SB, and/or information for specifying a manufacturer ofthe magnetic tape MT may also be embedded, and the pulse signal needonly be modulated in accordance with the information to be embedded.

In the example shown in FIG. 17 , head cores WH2A, WH2B, and WH2C areshown as an example of the plurality of head cores WH2, and gap patternsG1, G2, and G3 are shown as an example of the plurality of gap patternsG. The gap pattern G1 is formed in the head core WH2A. The gap patternG2 is formed in the head core WH2B. The gap pattern G3 is formed in thehead core WH2C.

The gap patterns G1 to G3 has the same geometrical characteristics aseach other. In the present embodiment, for example, the gap pattern G1is used for recording the servo pattern 58 (see FIG. 9 ) for the servoband SB3 (see FIG. 9 ), the gap pattern G2 is used for recording theservo pattern 58 (see FIG. 9 ) for the servo band SB2 (see FIG. 9 ), andthe gap pattern G3 is used for recording the servo pattern 58 (see FIG.9 ) for the servo band SB1 (see FIG. 9 ).

The gap pattern G1 is a straight line region pair consisting of straightline regions G1A and G1B. In addition, the gap pattern G2 is a straightline region pair consisting of straight line regions G2A and G2B. Inaddition, the gap pattern G3 is a straight line region pair consistingof straight line regions G3A and G3B.

In the present embodiment, the straight line region pair consisting ofthe straight line regions G1A and G1B, the straight line region pairconsisting of the straight line regions G2A and G2B, and the straightline region pair consisting of the straight line regions G3A and G3B areexamples of a “straight line region pair” according to the technology ofthe present disclosure. In addition, in the present embodiment, thestraight line regions G1A, G2A, and G3A are examples of a “firststraight line region” according to the technology of the presentdisclosure. In addition, in the present embodiment, the straight lineregions G1B, G2B, and G3B are examples of a “second straight lineregion” according to the technology of the present disclosure.

The pulse signal generator SW4 includes a first pulse signal generatorSW4A, a second pulse signal generator SW4B, and a third pulse signalgenerator SW4C. The first pulse signal generator SW4A is connected tothe head core WH2A. The second pulse signal generator SW4B is connectedto the head core WH2B. The third pulse signal generator SW4C isconnected to the head core WH2C.

In a case in which the gap pattern G1 is used for the servo band SB3(see FIG. 9 ), in a case in which the first pulse signal generator SW4Asupplies the pulse signal to the head core WH2A, the magnetic field isapplied from the gap pattern G1 to the servo band SB3 in response to thepulse signal, and the servo pattern 58 (see FIG. 9 ) is recorded in theservo band SB3.

For example, in a case in which the pulse signal for the servo pattern58A is supplied to the head core WH2A in a state in which the gappattern G1 faces the servo band SB3 of the magnetic tape MT that travelson the transport passage SW7, the servo pattern 58A (see FIG. 9 ) isrecorded in the servo band SB3. That is, the linear magnetization region60A1 (see FIG. 9 ) is recorded in the servo band SB3 by the straightline region G1A, and the linear magnetization region 60A2 (see FIG. 9 )is recorded in the servo band SB3 by the straight line region G1B.

In addition, for example, in a case in which the pulse signal for theservo pattern 58B is supplied to the head core WH2A in a state in whichthe gap pattern G1 faces the servo band SB3 of the magnetic tape MT thattravels on the transport passage SW7, the servo pattern 58B (see FIG. 9) is recorded in the servo band SB3. That is, the linear magnetizationregion 60B1 (see FIG. 9 ) is recorded in the servo band SB3 by thestraight line region G1A, and the linear magnetization region 60B2 (seeFIG. 9 ) is recorded in the servo band SB3 by the straight line regionG1B.

In a case in which the gap pattern G2 is used for the servo band SB2(see FIG. 9 ), in a case in which the second pulse signal generator SW4Bsupplies the pulse signal to the head core WH2B, the magnetic field isapplied from the gap pattern G2 to the servo band SB2 in response to thepulse signal, and the servo pattern 58 is recorded in the servo bandSB2.

For example, in a case in which the pulse signal for the servo pattern58A is supplied to the head core WH2B in a state in which the gappattern G2 faces the servo band SB2 of the magnetic tape MT that travelson the transport passage SW7, the servo pattern 58A (see FIG. 9 ) isrecorded in the servo band SB2. That is, the linear magnetization region60A1 is recorded in the servo band SB2 by the straight line region G2A,and the linear magnetization region 60A2 is recorded in the servo bandSB2 by the straight line region G2B.

In addition, for example, in a case in which the pulse signal for theservo pattern 58B is supplied to the head core WH2B in a state in whichthe gap pattern G2 faces the servo band SB2 of the magnetic tape MT thattravels on the transport passage SW7, the servo pattern 58B is recordedin the servo band SB2. That is, the linear magnetization region 60B1 isrecorded in the servo band SB2 by the straight line region G2A, and thelinear magnetization region 60B2 is recorded in the servo band SB2 bythe straight line region G2B.

In a case in which the gap pattern G3 is used for the servo band SB1(see FIG. 9 ), in a case in which the third pulse signal generator SW4Csupplies the pulse signal to the head core WH2C, the magnetic field isapplied from the gap pattern G3 to the servo band SB1 in response to thepulse signal, and the servo pattern 58 is recorded in the servo bandSB1.

For example, in a case in which the pulse signal for the servo pattern58A is supplied to the head core WH2C in a state in which the gappattern G3 faces the servo band SB1 of the magnetic tape MT that travelson the transport passage SW7, the servo pattern 58A is recorded in theservo band SB1. That is, the linear magnetization region 60A1 isrecorded in the servo band SB1 by the straight line region G3A, and thelinear magnetization region 60A2 is recorded in the servo band SB1 bythe straight line region G3B.

In addition, for example, in a case in which the pulse signal for theservo pattern 58B is supplied to the head core WH2C in a state in whichthe gap pattern G3 faces the servo band SB1 of the magnetic tape MT thattravels on the transport passage SW7, the servo pattern 58B is recordedin the servo band SB1. That is, the linear magnetization region 60B1 isrecorded in the servo band SB1 by the straight line region G3A, and thelinear magnetization region 60B2 is recorded in the servo band SB1 bythe straight line region G3B.

As an example, as shown in FIG. 18 , in the gap pattern G1, the straightline regions G1A and G1B are inclined in opposite directions withrespect to the straight line along the direction WD1, that is, theimaginary straight line C1. In other words, the straight line region G1Ais inclined in one direction (for example, the clockwise direction asviewed from the paper surface side of FIG. 18 ) with respect to theimaginary straight line C1. On the other hand, the straight line regionG1B is inclined in the other direction (for example, thecounterclockwise direction as viewed from the paper surface side of FIG.18 ) with respect to the imaginary straight line C1. In addition, thestraight line region G1A has a steeper inclined angle with respect tothe imaginary straight line C1 than the straight line region G1B. Here,“steep” means that, for example, the angle of the straight line regionG1A with respect to the imaginary straight line C1 is smaller than theangle of the straight line region G1B with respect to the imaginarystraight line C1. In addition, the positions of both ends of thestraight line region G1A and the positions of both ends of the straightline region G1B are aligned in the direction WD1. In addition, a totallength of the straight line region G1A is shorter than a total length ofthe straight line region G1B.

In the gap pattern G2, the straight line regions G2A and G2B areinclined in opposite directions with respect to the imaginary straightline C1. In other words, the straight line region G2A is inclined in onedirection (for example, the clockwise direction as viewed from the papersurface side of FIG. 18 ) with respect to the imaginary straight lineC1. On the other hand, the straight line region G2B is inclined in theother direction (for example, the counterclockwise direction as viewedfrom the paper surface side of FIG. 18 ) with respect to the imaginarystraight line C1. In addition, the straight line region G2A has asteeper inclined angle with respect to the imaginary straight line C1than the straight line region G2B. Here, “steep” means that, forexample, the angle of the straight line region G2A with respect to theimaginary straight line C1 is smaller than the angle of the straightline region G2B with respect to the imaginary straight line C1. Inaddition, the positions of both ends of the straight line region G2A andthe positions of both ends of the straight line region G2B are alignedin the direction WD1. In addition, a total length of the straight lineregion G2A is shorter than a total length of the straight line regionG2B.

In the gap pattern G3, the straight line regions G3A and G3B areinclined in opposite directions with respect to the imaginary straightline C1. In other words, the straight line region G3A is inclined in onedirection (for example, the clockwise direction as viewed from the papersurface side of FIG. 18 ) with respect to the imaginary straight lineC1. On the other hand, the straight line region G3B is inclined in theother direction (for example, the counterclockwise direction as viewedfrom the paper surface side of FIG. 18 ) with respect to the imaginarystraight line C1. In addition, the straight line region G3A has asteeper inclined angle with respect to the imaginary straight line C1than the straight line region G3B. Here, “steep” means that, forexample, the angle of the straight line region G3A with respect to theimaginary straight line C1 is smaller than the angle of the straightline region G3B with respect to the imaginary straight line C1. Inaddition, the positions of both ends of the straight line region G3A andthe positions of both ends of the straight line region G3B are alignedin the direction WD1. In addition, a total length of the straight lineregion G3A is shorter than a total length of the straight line regionG3B.

On the front surface WH1A, the long side WH1Aa is longer than the widthof the magnetic tape MT. The short side WH1Ab is a length in which thegap patterns G1, G2, and G3 are contained. The substrate WH1 is disposedon the magnetic tape MT in a posture in which the orientation of thelong side WH1Aa and the longitudinal direction LD are orthogonal to eachother. That is, the substrate WH1 is disposed on the front surface 31side of the magnetic tape MT in a state in which the plurality of gappatterns G and the front surface 31 face each other, and in a posture inwhich the orientation of the long side WH1Aa and the longitudinaldirection LD are orthogonal to each other.

The phases of the pulse signals used between the gap patterns G1, G2,and G3 (that is, as shown in FIG. 17 , the pulse signal supplied fromthe first pulse signal generator SW4A (see FIG. 17 ) to the head coreWH2A, the pulse signal supplied from the second pulse signal generatorSW4B (see FIG. 17 ) to the head core WH2B, and the pulse signal suppliedfrom the third pulse signal generator SW4C (see FIG. 17 ) to the headcore WH2C) deviate from each other.

Specifically, the pulse signal generator SW4 (see FIG. 17 ) supplies thepulse signal with a delay of a predetermined time to each of the gappatterns G1, G2, and G3 from one side to the other side in a directionin which the gap patterns G1, G2, and G3 are arranged. Here, one siderefers to a side of the gap pattern G3, and the other side refers to aside of the gap pattern G1. In the example shown in FIG. 18 , the pulsesignal is first supplied to the gap pattern G3, the pulse signal issecondly supplied to the gap pattern G2 with the delay of thepredetermined time, and then the pulse signal is supplied to the gappattern G1 with the delay of the predetermined time.

The predetermined time is a time determined in advance in accordancewith the predetermined interval described above (that is, thepredetermined interval calculated from Expression (1)) and a travelingspeed of the magnetic tape MT that travels on the transport passage SW7,and is a fixed value derived in advance by a test with an actual machineand/or a computer simulation in order to realize the predeterminedinterval, for example.

It should be noted that the predetermined time may be a variable valuethat is changed in accordance with various conditions. In this case, forexample, the predetermined time is calculated from an arithmeticexpression having the predetermined interval as a first independentvariable, the traveling speed of the magnetic tape MT that travels onthe transport passage SW7 as a second independent variable, and thepredetermined time as a dependent variable. Examples of thepredetermined interval used as the first independent variable include aninterval designated by the user or the like of the servo writer SW asthe interval in the longitudinal direction LD of the pair of frames 56having the correspondence relationship between the servo bands SBadjacent to each other in the width direction WD. Examples of thetraveling speed used as the second independent variable include atraveling speed designated by the user of the servo writer SW or thelike, and a traveling speed measured by a sensor (not shown).

In the servo pattern recording step, in a state in which the position ofthe gap pattern G1 corresponds to the position of the servo band SB3,the position of the gap pattern G2 corresponds to the position of theservo band SB2, and the position of the gap pattern G3 corresponds tothe position of the servo band SB1, the magnetic tape MT travels on thetransport passage SW7 at a regular speed. Moreover, in this state, thepulse signal for the servo pattern 58A and the pulse signal for theservo pattern 58B are alternately supplied to the head core WH2A, thehead core WH2B, and the head core WH2C.

In a case in which the pulse signal for the servo pattern 58A issupplied to the head core WH2A, the head core WH2B, and the head coreWH2C in the deviated phase, the servo patterns 58A are recorded in theservo band SB3, the servo band SB2, and the servo band SB1 in a state ofdeviating from each other at the predetermined interval in thelongitudinal direction LD. In addition, in a case in which the pulsesignal for the servo pattern 58B is supplied to the head core WH2A, thehead core WH2B, and the head core WH2C in the deviated phase, the servopatterns 58B are recorded in the servo band SB3, the servo band SB2, andthe servo band SB1 in a state of deviating from each other at thepredetermined intervals in the longitudinal direction LD.

Here, the geometrical characteristic of the gap pattern G on the frontsurface WH1A will be described with reference to FIG. 19 .

As an example, as shown in FIG. 19 , the geometrical characteristic ofthe gap pattern G on the front surface WH1A can be expressed by using animaginary straight line region pair 68. The imaginary straight lineregion pair 68 consists of an imaginary straight line region 68A and animaginary straight line region 68B. In the present embodiment, theimaginary straight line region pair 68 is an example of a “pair ofimaginary straight line regions” according to the technology of thepresent disclosure, the imaginary straight line region 68A is an exampleof “one imaginary straight line region” according to the technology ofthe present disclosure, and the imaginary straight line region 68B is anexample of “the other imaginary straight line region” according to thetechnology of the present disclosure.

The imaginary straight line region pair 68 is the imaginary straightline region pair having the same geometrical characteristic as the gappattern G shown in FIG. 18 . The imaginary straight line region pair 68is the imaginary straight line region pair used for convenience fordescribing the geometrical characteristic of the gap pattern G on thefront surface WH1A, and is not an actually present straight line regionpair.

In the present embodiment, for example, the imaginary straight lineregion 68A has the same geometrical characteristic as the straight lineregion G1A shown in FIG. 18 , and the imaginary straight line region 68Bhas the same geometrical characteristic as the straight line region G1Bshown in FIG. 18 .

A center O2 is provided in the imaginary straight line region pair 68.For example, the center O2 is the center of a line segment L2 connectingthe center of the imaginary straight line region 68A and the center ofthe imaginary straight line region 68B.

The imaginary straight line region 68A and the imaginary straight lineregion 68B are inclined line-symmetrically with respect to the imaginarystraight line C1. Here, in a case in which the imaginary straight lineregion pair 68 and the imaginary linear region pair 62 shown in FIG. 10in a case in which the entirety of the imaginary straight line regionpair 68 is inclined with respect to the imaginary straight line C1 byinclining a symmetry axis SA2 of the imaginary straight line region 68Aand the imaginary straight line region 68B at an angle b (for example,10 degrees) with respect to the imaginary straight line C1 with thecenter O2 as the rotation axis are compared, the shortage part and theunnecessary part are generated in the imaginary straight line regionpair 68. Here, the shortage part refers to the shortage part in a casein which the servo pattern recording head WH records the servo pattern58 in the magnetic tape MT, and the unnecessary part refers to theunnecessary part in a case in which the servo pattern recording head WHrecords the servo pattern 58 in the magnetic tape MT. In the exampleshown in FIG. 19 , an aspect is shown in which the shortage part and theunnecessary part are generated in the imaginary straight line region68B.

Therefore, by compensating for the shortage part and removingunnecessary part, the positions of both ends of the imaginary straightline region 68A and the positions of both ends of the imaginary straightline region 68B are aligned in the direction WD1.

The geometrical characteristic of the imaginary straight line regionpair 68 obtained as described above (that is, the geometricalcharacteristic of the imaginary gap pattern) corresponds to thegeometrical characteristic of the actual gap pattern G. That is, on thefront surface WH1A (see FIG. 18 ), the gap pattern G having thegeometrical characteristic corresponding to the geometricalcharacteristic of the imaginary straight line region pair 68 obtained byaligning the positions of both ends of the imaginary straight lineregion 68A and the positions of both ends of the imaginary straight lineregion 68B in the direction WD1 is formed.

Next, an action of the magnetic tape system 10 will be described.

The magnetic tape cartridge 12 accommodates the magnetic tape MT shownin FIG. 9 (see FIGS. 9 and 11 ). The magnetic tape cartridge 12 isloaded into the magnetic tape drive 14. In the magnetic tape drive 14,in a case in which the magnetic tape MT is subjected to the magneticprocessing by the magnetic element unit 42 (see FIGS. 3 and 15 ), themagnetic tape MT is pulled out from the magnetic tape cartridge 12, andthe servo pattern 58 in the servo band SB is read by the servo readingelement SR of the magnetic head 28.

As shown in FIGS. 9 and 10 , the linear magnetization regions 60A1 and60A2 included in the servo pattern 58A recorded in the servo band SB ofthe magnetic tape MT are inclined in opposite directions with respect tothe imaginary straight line C1. On the other hand, as shown in FIG. 13 ,the magnetic head 28 is also inclined to the upstream side in theforward direction by the angle β (that is, the angle β counterclockwiseas viewed from the paper surface side of FIG. 13 ) on the magnetic tapeMT. In a case in which the servo pattern 58A is read by the servoreading element SR in this state, since the angle formed by the linearmagnetization region 60A1 and the servo reading element SR and the angleformed by the linear magnetization region 60A2 and the servo readingelement SR are close to each other, the variation in the servo signaldue to the azimuth loss is smaller than the variation generated betweenthe servo signal derived from the linear magnetization region 54A1included in the known servo pattern 52A in the related art and the servosignal derived from the linear magnetization region 54A2 included in theknown servo pattern 52A in the related art.

As a result, the variation between the servo signal derived from thelinear magnetization region 60A1 and the servo signal derived from thelinear magnetization region 60A2 is smaller than the variation generatedbetween the servo signal derived from the linear magnetization region54A1 included in the known servo pattern 52A in the related art and theservo signal derived from the linear magnetization region 54A2 includedin the known servo pattern 52A in the related art, and the servo signalhaving higher reliability than the servo signal obtained from the knownservo pattern 52A in the related art can be obtained (hereinafter, thiseffect is also referred to as “first effect”). It should be noted that,as shown in FIG. 13 , also in a case in which the servo pattern 58B isread by the servo reading element SR in a state in which the magnetichead 28 on the magnetic tape MT is inclined to the upstream side in theforward direction at the angle β (that is, the angle β counterclockwiseas viewed from the paper surface side of FIG. 13 ), the same effect asthe first effect (hereinafter, this effect is also referred to as“second effect”) can be obtained.

By the way, in a case in which the positions of both ends of the linearmagnetization region 60A1 and the positions of both ends of the linearmagnetization region 60A2 are not aligned in the width direction WD, oneend portion of the linear magnetization region 60A1 is read by the servoreading element SR, but one end portion of the linear magnetizationregion 60A2 are not read, or the other end portion of the linearmagnetization region 60A1 is read by the servo reading element SR, butthe other end portion of the linear magnetization region 60A2 are notread.

Therefore, in the magnetic tape MT according to the present embodiment,in the servo band SB, the positions of both ends of the linearmagnetization region 60A1 (that is, the positions of both ends of eachof the five magnetization straight lines 60A1 a) and the positions ofboth ends of the linear magnetization region 60A2 (that is, thepositions of both ends of each of the five magnetization straight lines60A2 a) are aligned in the width direction WD. Therefore, in a case inwhich the servo pattern 58A is read by the servo reading element SR, ascompared with a case in which the positions of both ends of the linearmagnetization region 60A1 and the positions of both ends of the linearmagnetization region 60A2 are not aligned in the width direction WD, thelinear magnetization regions 60A1 and 60A2 can be read by the servoreading element SR without excess or deficiency. As a result, ascompared with a case in which the positions of both ends of the linearmagnetization region 60A1 and the positions of both ends of the linearmagnetization region 60A2 are not aligned in the width direction WD, theservo signal having high reliability can be obtained (hereinafter, thiseffect is referred to as “third effect”). It should be noted that, in acase in which the servo pattern 58B is read by the servo reading elementSR, the same effect as the third effect (hereinafter, this effect isalso referred to as a “fourth effect”) can be obtained.

As shown in FIGS. 9 and 10 , although the gradient of the linearmagnetization region 60A1 with respect to the imaginary straight line C1is steeper than the gradient of the linear magnetization region 60A2with respect to the imaginary straight line C1, in a case in which thetotal length of the linear magnetization region 60A1 is longer than thetotal length of the linear magnetization region 60A2, a part read by theservo reading element SR and a part that is not read are generatedbetween the linear magnetization region 60A1 and the linearmagnetization region 60A2. In addition, even in a case in which thetotal length of the linear magnetization region 60B1 is longer than thetotal length of the linear magnetization region 60B2, the part read bythe servo reading element SR and the part that is not read are generatedbetween the linear magnetization region 60B1 and the linearmagnetization region 60B2. Therefore, in the magnetic tape MT accordingto the present embodiment, the total length of the linear magnetizationregion 60A1 is shorter than the total length of the linear magnetizationregion 60A2, and the total length of the linear magnetization region60B1 is shorter than the total length of the linear magnetization region60B2. As a result, the linear magnetization regions 60A1 and 60A2 can beread by the servo reading element SR and the linear magnetizationregions 60B1 and 60B2 can be read by the servo reading element SRwithout excess or deficiency (hereinafter, this effect is referred to as“fifth effect”).

In addition, in the magnetic tape MT according to the presentembodiment, the linear magnetization region 60A1 is a set of fivemagnetization straight lines 60A1 a, and the linear magnetization region60A2 is a set of five magnetization straight lines 60A2 a. In addition,the linear magnetization region 60B1 is a set of four magnetizationstraight lines 60B1 a, and the linear magnetization region 60B2 is a setof four magnetization straight lines 60B2 a. Therefore, an amount ofinformation obtained from the servo pattern 58 can be increased ascompared with a case in which each linear magnetization region consistsof one magnetization straight line, and as a result, highly accurateservo control can be realized (hereinafter, this effect is referred toas “sixth effect”).

In addition, in the magnetic tape MT according to the presentembodiment, the geometrical characteristic of the linear magnetizationregion pair 60A on the magnetic tape MT corresponds to the geometricalcharacteristic in which the positions of both ends of the imaginarylinear region 62A and the positions of both ends of the imaginary linearregion 62B are aligned in the width direction WD in a case in which theentirety of the imaginary linear region pair 62 is inclined with respectto the imaginary straight line C1 by inclining, with respect to theimaginary straight line C1, the symmetry axis SA1 of the imaginarylinear region pair 62. Therefore, the variation between the servo signalderived from the linear magnetization region 60A1 and the servo signalderived from the linear magnetization region 60A2 can be made smallerthan a case in which the servo pattern 52A having the known geometricalcharacteristic in the related art is read by the servo reading elementSR. As a result, it is possible to obtain the servo signal having higherreliability than the servo signal obtained from the servo pattern 52Ahaving the known geometrical characteristic in the related art(hereinafter, this effect is referred to as “seventh effect”).

It should be noted that the linear magnetization region pair 60B isdifferent from the linear magnetization region pair 60A only in that thelinear magnetization region 60B1 is provided instead of the linearmagnetization region 60A1, and the linear magnetization region 60B2 isprovided instead of the linear magnetization region 60A2. The linearmagnetization region pair 60B configured as described above is also readby the servo reading element SR in the same manner as the linearmagnetization region pair 60A. Therefore, the variation between theservo signal derived from the linear magnetization region 60B1 and theservo signal derived from the linear magnetization region 60B2 can bemade smaller than a case in which the servo pattern 52B having the knowngeometrical characteristic in the related art is read by the servoreading element SR. As a result, it is possible to obtain the servosignal having higher reliability than the servo signal obtained from theservo pattern 52B having the known geometrical characteristic in therelated art (hereinafter, this effect is referred to as “eightheffect”).

In the present embodiment, a pair of servo patterns 58 corresponding toeach other between the servo bands SB is read by the servo readingelements SR1 and SR2 included in the magnetic head 28. In addition, inthe present embodiment, the magnetic head 28 is used in a state of beingskewed on the magnetic tape MT (see FIGS. 13 to 15 ). Here, in a case inwhich the pair of servo patterns 58 corresponding to each other betweenthe servo bands SB is tentatively disposed in the longitudinal directionLD without deviating at the predetermined intervals, a time differenceis generated between a timing at which one servo pattern 58 of the pairof servo patterns 58 corresponding to each other between the servo bandsSB is read and a timing at which the other servo pattern 58 is read.Therefore, in the magnetic tape MT according to the present embodiment,the servo patterns 58 corresponding to each other between the servobands SB deviate from each other at the predetermined intervals in thelongitudinal direction LD between the servo bands SB adjacent to eachother in the width direction WD. As a result, as compared with a case inwhich the pair of servo patterns 58 corresponding to each other betweenthe servo bands SB is tentatively disposed without deviating at thepredetermined intervals, the time difference generated between thetiming at which one servo pattern 58 of the pair of servo patterns 58corresponding to each other between the servo bands SB adjacent to eachother in the width direction WD is read and the timing at which theother servo pattern 58 is read can be reduced (hereinafter, this effectis referred to as “ninth effect”).

In the present embodiment, the servo band SB is divided by the pluralityof frames 56 (see FIGS. 9 and 11 ). The frame 56 is defined based on thepair of servo patterns 58 (that is, the servo patterns 58A and 58B). Inaddition, in the present embodiment, the pair of servo patterns 58included in the pair of frames 56 having the correspondence relationshipbetween the servo bands SB adjacent to each other in the width directionWD is read by the servo reading elements SR1 and SR2 included in themagnetic head 28. In addition, in the present embodiment, the magnetichead 28 is used in a state of being skewed on the magnetic tape MT (seeFIGS. 13 to 15 ). Here, in a case in which the pair of servo patterns 58included in the pair of frames 56 having the correspondence relationshipbetween the servo bands SB adjacent to each other in the width directionWD is tentatively disposed in the longitudinal direction LD withoutdeviating at the predetermined intervals, a time difference is generatedbetween a timing at which one servo pattern 58 of the pair of servopatterns 58 is read and a timing at which the other servo pattern 58 isread. Therefore, in the magnetic tape MT according to the presentembodiment, the pair of servo patterns 58 included in the pair of frames56 having the correspondence relationship between the servo bands SBadjacent to each other in the width direction WD deviate from each otherat the predetermined intervals in the longitudinal direction LD betweenthe servo bands SB adjacent to each other in the width direction WD. Asa result, as compared with a case in which the pair of frames 56corresponding to each other between the servo bands SB adjacent to eachother in the width direction WD is disposed without deviating at thepredetermined intervals, the time difference generated between thetiming at which one servo pattern 58 of the pair of servo patterns 58included in the pair of frames 56 having the correspondence relationshipbetween the servo bands SB adjacent to each other in the width directionWD is read and the timing at which the other servo pattern 58 is readcan be reduced (hereinafter, this effect is referred to as “tentheffect”).

In the present embodiment, as shown in FIG. 11 , the predeterminedinterval is defined based on the angle α formed by the interval betweenthe frame 56 having no correspondence relationship between the servobands SB adjacent to each other in the width direction WD, and theimaginary straight line C1, the servo band pitch, and the total lengthof the frame 56 in the longitudinal direction. That is, thepredetermined interval is defined by Expression (1) and is calculatedfrom Expression (1). Therefore, the predetermined interval can be easilyobtained as compared with a case in which the predetermined interval isdefined without using any of the angle α, the servo band pitch, and thetotal length of the frame 56 in the longitudinal direction (hereinafter,this effect is referred to as “eleventh effect”).

In the present embodiment, the servo signal, which is the result ofreading the servo pattern 58 by the servo reading element SR, isdetected by using the autocorrelation coefficient (see FIG. 15 ). As aresult, the servo signal can be detected more accurately than a case inwhich the servo signal is detected by using only a method of determiningwhether or not the signal level exceeds a threshold value (hereinafter,this effect is referred to as “twelfth effect”).

Next, an action of the servo writer SW will be described.

In the servo writer SW, in a case in which the servo pattern 58 isrecorded in the magnetic tape MT by the servo pattern recording head WH,the magnetic tape MT is sent to the transport passage SW7, and themagnetic tape MT is caused to travel at a regular speed. In this case,in a state in which the position of the gap pattern G1 corresponds tothe position of the servo band SB3, the position of the gap pattern G2corresponds to the position of the servo band SB2, and the position ofthe gap pattern G3 corresponds to the position of the servo band SB1,the magnetic tape MT is caused to travel. In this state, the pulsesignal for the servo pattern 58A and the pulse signal for the servopattern 58B are alternately supplied to the head core WH2A, the headcore WH2B, and the head core WH2C of the servo pattern recording headWH.

The gap pattern G consists of the pair of non-parallel straight lineregions. The pair of non-parallel straight line regions refers to thestraight line region having the same geometrical characteristic as thegeometrical characteristic of the magnetization straight line 60A1 apositioned on the most upstream side in the forward direction among thefive magnetization straight lines 60A1 a included in the linearmagnetization region 60A1 shown in FIG. 9 , and the straight line regionhaving the same geometrical characteristic as the geometricalcharacteristic of the magnetization straight line 60A2 a positioned onthe most upstream side in the forward direction among the fivemagnetization straight lines 60A2 a included in the linear magnetizationregion 60A2 shown in FIG. 9 . In addition, the gap patterns G1, G2, andG3 deviate from each other at the predetermined intervals along thedirection LD1 corresponding to the longitudinal direction LD.

Therefore, in a case in which the pulse signal for the servo pattern 58Ais supplied to the head core WH2A, the head core WH2B, and the head coreWH2C in the same phase, the servo patterns 58A are recorded in the servoband SB3, the servo band SB2, and the servo band SB1 in a state ofdeviating from each other at the predetermined intervals in thelongitudinal direction LD. In addition, in a case in which the pulsesignal for the servo pattern 58B is supplied to the head core WH2A, thehead core WH2B, and the head core WH2C in the same phase, the servopatterns 58B are recorded in the servo band SB3, the servo band SB2, andthe servo band SB1 in a state of deviating from each other at thepredetermined intervals in the longitudinal direction LD.

In a case in which the servo pattern 58A recorded in the servo band SBof the magnetic tape MT obtained as described above is read by the servoreading element SR included in the magnetic head 28 in a skewed state onthe magnetic tape MT, the first to twelfth effects can be obtained.

As shown in FIG. 20 as a first comparative example, even in a case inwhich a servo pattern recording head Ha is used, the servo patterns 58can be recorded in the servo band SB3, the servo band SB2, and the servoband SB1 in a state of deviating at the predetermined intervals in thelongitudinal direction LD. The servo pattern recording head Ha isdifferent from the servo pattern recording head WH in that a substrateHα1 is provided instead of the substrate WH1. The substrate Hα1 isformed in a rectangular parallelepiped shape, and is disposed to crossthe front surface 31 of the magnetic tape MT that travels on thetransport passage SW7 along the width direction WD. A front surface Hα1Aof the substrate Hα1 is a rectangle having a long side Hα1Aa and a shortside Hα1Ab, and the long side Hα1Aa crosses the front surface 31 of themagnetic tape MT along the width direction WD.

The long side Hα1Aa is longer than the width of the magnetic tape MT.The long side Hα1Aa direction and the width direction WD match, and thesubstrate Hα1 is disposed on the front surface 31 side of the magnetictape MT in a state in which the plurality of gap patterns G and thefront surface 31 face to each other and in a state of crossing themagnetic tape MT in the width direction WD.

In the servo pattern recording head Ha, the gap patterns G1, G2, and G3deviate from each other at the predetermined intervals described above(that is, the predetermined interval calculated from Expression (1)) ina direction LD1 corresponding to the longitudinal direction LD (forexample, the same direction as the longitudinal direction LD), betweenthe gap patterns G adjacent to each other along the direction WD1.Moreover, a direction of the short side Hα1Ab and the direction LD1match, and the short side Hα1Ab is a length in which all of the gappatterns G1, G2, and G3 are contained. That is, the length of the shortside Hα1Ab is set to be a length in which at least the amount of the gappatterns G1 to G3 deviating from the gap pattern G1 to the gap patternG3 along the direction LD1 is compensated. In the servo patternrecording head Ha configured as described above, the pulse signal havingthe same phase is supplied to each of the gap patterns G1, G2, and G3 torecord the plurality of servo patterns 58 in the plurality of servobands SB, respectively (see FIG. 9 ).

On the other hand, in the servo pattern recording head WH, the gappatterns G1, G2, and G3 are arranged in a straight line in the directionorthogonal to the direction LD1 and the pulse signal is delayed by thepredetermined time, so that the arrangement of the plurality of servopatterns 58 shown in FIG. 9 can be realized without deviating the gappatterns G1, G2, and G3 in the direction LD1. The short side WH1Ab canbe made shorter than the short side Hα1Ab by an amount that the gappatterns G1, G2, and G3 do not need to deviate from each other in thedirection LD1. The fact that the short side WH1Ab is shorter than theshort side Hα1Ab means that an area of the front surface WH1A is smallerthan an area of the front surface Hα1A. As a result, an area in whichthe front surface WH1A contacts the front surface 31 of the magnetictape MT (that is, an area of the sliding surface WH1Ax shown in FIG. 17) can be made smaller than an area in which the front surface Hα1A shownin FIG. 20 contacts the front surface 31 of the magnetic tape MT, sothat in the servo pattern recording head WH, the friction generatedbetween the magnetic tape MT and the front surface WH1A can besuppressed as compared with the servo pattern recording head Ha. Inaddition, the suppression of the friction contributes to stabilizing thetraveling of the magnetic tape MT.

As shown in FIG. 21 as a second comparative example, even in a case inwhich a servo pattern recording head HP is used, the servo patterns 58can be recorded in the servo band SB3, the servo band SB2, and the servoband SB1 in a state of deviating at the predetermined intervals in thelongitudinal direction LD. The servo pattern recording head HP isdifferent from the servo pattern recording head WH in that a substrateHβ1 is provided instead of the substrate WH1. The substrate Hβ1 isformed in a rectangular parallelepiped shape, and is disposed todiagonally cross the front surface 31 of the magnetic tape MT thattravels on the transport passage SW7. A front surface Hβ1A of thesubstrate Hβ1 is a rectangle having a long side Hβ1Aa and a short sideHβ1Ab, and the long side Hβ1Aa diagonally crosses the front surface 31of the magnetic tape MT.

In the servo pattern recording head HP, the gap patterns G1, G2, and G3deviate from each other at the predetermined intervals described above(that is, the predetermined interval calculated from Expression (1)) inthe direction LD1, between the gap patterns G adjacent to each otheralong the direction WD1. The short side Hβ1Ab is a length in which thegap patterns G1, G2, and G3 are contained. That is, the length of theshort side Hβ1Ab is set to be a length in which at least the amount ofthe gap patterns G1 to G3 deviating from the gap pattern G1 to the gappattern G3 along the direction LD1 is compensated.

In the servo pattern recording head HP, the substrate Hβ1 is inclined onthe front surface 31 side of the magnetic tape MT along the frontsurface 31 of the magnetic tape MT with respect to the imaginarystraight line C1 at the angle γ at which deviation at the predeterminedintervals is absorbed in a state in which the plurality of gap patternsG and the front surface 31 face to each other. In the example shown inFIG. 21 , an aspect is shown in which an extension line C5 of the longside Hβ1Aa is inclined along the front surface 31 of the magnetic tapeMT with respect to the imaginary straight line C1 at the angle γ. In theservo pattern recording head HP configured as described above, the pulsesignal having the same phase is supplied to each of the gap patterns G1,G2, and G3 to record the plurality of servo patterns 58 in the pluralityof servo bands SB, respectively (see FIG. 9 ).

On the other hand, in the servo pattern recording head WH, the gappatterns G1, G2, and G3 are arranged in a straight line on the frontsurface WH1A in the direction orthogonal to the direction LD1 and thepulse signal is delayed by the predetermined time, so that thearrangement of the plurality of servo patterns 58 shown in FIG. 9 can berealized without deviating the gap patterns G1, G2, and G3 in thedirection LD1. Therefore, in the servo pattern recording head WH, it isnot necessary to incline the substrate WH1 on the front surface 31 ofthe magnetic tape MT. The fact that it is not necessary to incline thesubstrate WH1 on the front surface 31 of the magnetic tape MT means thatinclination work of the substrate WH1 is not necessary. In addition, thephenomenon that the magnetic tape MT is biased in the width direction WDdue to the inclination of the substrate WH1 is less likely to occur.

In addition, in the servo writer SW, the signal having the deviatedphase is used as the pulse signal used between the plurality of gappatterns G. The pulse signal for the servo pattern 58A and the pulsesignal for the servo pattern 58B are alternately supplied to the headcore WH2A, the head core WH2B, and the head core WH2C. In the servowriter SW, the gap patterns G1, G2, and G3 deviate from each other atthe predetermined intervals in the direction LD1. Therefore, bysupplying the pulse signal for the servo pattern 58A in the deviatedphase to the head core WH2A, the head core WH2B, and the head core WH2C,the servo writer SW can record the servo patterns 58A in the servo bandsSB1 to SB3 by the deviation at the predetermined intervals in thelongitudinal direction LD between the servo bands SB adjacent to eachother in the width direction WD. In addition, by supplying the pulsesignal for the servo pattern 58B in the deviated phase to the head coreWH2A, the head core WH2B, and the head core WH2C, the servo writer SWcan record the servo patterns 58B in the servo bands SB1 to SB3 by thedeviation at the predetermined intervals in the longitudinal directionLD between the servo bands SB adjacent to each other in the widthdirection WD.

In addition, in the servo writer SW, the control device SW5 operates asthe position detection unit 30B shown in FIG. 14 to obtain a positiondetection result from the servo pattern reading result, and uses theposition detection result to determine whether the servo pattern 58 iscorrect or not to thereby inspect the servo band SB. The control deviceSW5 operating as the position detection unit 30B can detect the servosignal with high accuracy compared with a case in which only a methodfor determining whether the signal level exceeds a threshold or not isused to detect the servo signal, so that the servo writer SW can alsoinspect the servo band SB with high accuracy.

It should be noted that, in the embodiment described above, the formexample has been described in which the servo band SB is divided by theplurality of frames 56 along the longitudinal direction LD, but thetechnology of the present disclosure is not limited to this. Forexample, as shown in FIG. 22 , the servo band SB may be divided by aframe 70 along the longitudinal direction LD. The frame 70 is defined bya set of servo patterns 72. A plurality of servo patterns 72 arerecorded in the servo band SB along the longitudinal direction LD.Similar to the plurality of servo patterns 58, the plurality of servopatterns 72 are disposed at regular intervals along the longitudinaldirection LD.

In the example shown in FIG. 22 , servo patterns 72A and 72B are shownas an example of the set of servo patterns 72. Each of the servopatterns 72A and 72B is an M-shaped magnetized servo pattern. The servopatterns 72A and 72B are adjacent to each other along the longitudinaldirection LD, and the servo pattern 72A is positioned on the upstreamside in the forward direction and the servo pattern 72B is positioned onthe downstream side in the forward direction in the frame 70.

As an example, as shown in FIG. 23 , the servo pattern 72 consists of alinear magnetization region pair 74. The linear magnetization regionpair 74 is classified into a linear magnetization region pair 74A and alinear magnetization region pair 74B.

The servo pattern 72A consists of a set of linear magnetization regionpairs 74A. The set of linear magnetization region pairs 74A are disposedin a state of being adjacent to each other along the longitudinaldirection LD.

In the example shown in FIG. 23 , linear magnetization regions 74A1 and74A2 are shown as an example of the linear magnetization region pair74A. The linear magnetization region pair 74A is configured in the samemanner as the linear magnetization region pair 60A described in theabove embodiment, and has the same geometrical characteristic as thelinear magnetization region pair 60A. That is, the linear magnetizationregion 74A1 is configured in the same manner as the linear magnetizationregion 60A1 described in the above embodiment, and has the samegeometrical characteristic as the linear magnetization region 60A1, andthe linear magnetization region 74A2 is configured in the same manner asthe linear magnetization region 60A2 described in the above embodiment,and has the same geometrical characteristic as the linear magnetizationregion 60A2.

The servo pattern 72B consists of a set of linear magnetization regionpairs 74B. The set of linear magnetization region pairs 74B are disposedin a state of being adjacent to each other along the longitudinaldirection LD.

In the example shown in FIG. 23 , linear magnetization regions 74B1 and74B2 are shown as an example of the linear magnetization region pair74B. The linear magnetization region pair 74B is configured in the samemanner as the linear magnetization region pair 60B described in theabove embodiment, and has the same geometrical characteristic as thelinear magnetization region pair 60B. That is, the linear magnetizationregion 74B1 is configured in the same manner as the linear magnetizationregion 60B1 described in the above embodiment, and has the samegeometrical characteristic as the linear magnetization region 60B1, andthe linear magnetization region 74B2 is configured in the same manner asthe linear magnetization region 60B2 described in the above embodiment,and has the same geometrical characteristic as the linear magnetizationregion 60B2.

As an example, as shown in FIG. 24 , the servo pattern recording head WHused for recording the servo pattern 72 is different from the servopattern recording head WH described in the above embodiment (that is,the servo pattern recording head WH used for recording the servo pattern58) in that a gap pattern G4 is provided instead of the gap pattern G1,a gap pattern G5 is provided instead of the gap pattern G2, and a gappattern G6 is provided instead of the gap pattern G3.

The gap pattern G4 consists of straight line regions G4A, G4B, G4C, andG4D. The straight line regions G4A and G4B are used for recording onelinear magnetization region pair 74A of the set of linear magnetizationregion pairs 74A shown in FIG. 23 (for example, the linear magnetizationregion pair 74A on the upstream side in the forward direction), and thestraight line regions G4C and G4D are used for recording the otherlinear magnetization region pair 74A of the set of linear magnetizationregion pairs 74A shown in FIG. 23 (for example, the linear magnetizationregion pair 74A on the downstream side in the forward direction). Inaddition, the straight line regions G4A and G4B are used for recordingone linear magnetization region pair 74B of the set of linearmagnetization region pairs 74B shown in FIG. 23 (for example, the linearmagnetization region pair 74B on the upstream side in the forwarddirection), and the straight line regions G4C and G4D are used forrecording the other linear magnetization region pair 74B of the set oflinear magnetization region pairs 74B shown in FIG. 23 (for example, thelinear magnetization region pair 74B on the downstream side in theforward direction).

The configurations of the straight line regions G4A and G4B are the sameas the configurations of the straight line regions G1A and G1B. That is,the straight line regions G4A and G4B have the same geometricalcharacteristics as the straight line regions G1A and G1B. Theconfigurations of the straight line regions G4C and G4D are the same asthe configurations of the straight line regions G4A and G4B. That is,the straight line regions G4C and G4D have the same geometricalcharacteristics as the straight line regions G4A and G4B.

The gap pattern G5 consists of straight line regions G5A, G5B, G5C, andG5D. The configurations of the straight line regions G5A, G5B, G5C, andG5D are the same as the configurations of the straight line regions G4A,G4B, G4C, and G4D. That is, the straight line regions G5A, G5B, G5C, andG5D have the same geometrical characteristics as the straight lineregions G4A, G4B, G4C, and G4D.

The gap pattern G6 consists of straight line regions G6A, G6B, G6C, andG6D. The configurations of the straight line regions G6A, G6B, G6C, andG6D are the same as the configurations of the straight line regions G4A,G4B, G4C, and G4D. That is, the straight line regions G6A, G6B, G6C, andG6D have the same geometrical characteristics as the straight lineregions G4A, G4B, G4C, and G4D.

The gap patterns G4, G5, and G6 configured as described above arearranged in a straight line along the long side WH1Aa as in theembodiment described above.

The long side WH1Aa of the front surface WH1A is longer than the widthof the magnetic tape MT. The short side WH1Ab of the front surface WH1Ais a length in which all of the gap patterns G4, G5, and G6 arecontained. The long side WH1Aa direction of the front surface WH1Amatches the width direction WD, and the short side WH1Ab direction ofthe front surface WH1A matches the longitudinal direction LD. Thesubstrate WH1 is disposed on the front surface 31 side of the magnetictape MT in a state in which the plurality of gap patterns G and thefront surface 31 face each other and in a state of crossing the magnetictape MT along the width direction WD.

The pulse signals used between the gap patterns G4, G5, and G6 (that is,as shown in FIG. 24 , the pulse signal supplied from the first pulsesignal generator SW4A to the head core WH2A, the pulse signal suppliedfrom the second pulse signal generator SW4B to the head core WH2B, andthe pulse signal supplied from the third pulse signal generator SW4C tothe head core WH2C) are signals delayed by a predetermined time in orderfrom the gap patterns G6, G5, and G4, as described in the aboveembodiment.

In the servo pattern recording step, in a state in which the position ofthe gap pattern G4 corresponds to the position of the servo band SB3,the position of the gap pattern G5 corresponds to the position of theservo band SB2, and the position of the gap pattern G6 corresponds tothe position of the servo band SB1, the magnetic tape MT travels alongthe transport passage SW7 at a regular speed. Moreover, in this state,the pulse signal for the servo pattern 72A and the pulse signal for theservo pattern 72B are alternately supplied to the head core WH2A, thehead core WH2B, and the head core WH2C.

Here, in a case in which the pulse signal for the servo pattern 72A issupplied to the head core WH2A, the head core WH2B, and the head coreWH2C at the same timing as the timing described in the above embodiment,the servo patterns 72A are recorded in the servo band SB3, the servoband SB2, and the servo band SB1 in a state of deviating from each otherat the predetermined intervals in the longitudinal direction LD. Inaddition, in a case in which the pulse signal for the servo pattern 72Bis supplied to the head core WH2A, the head core WH2B, and the head coreWH2C at the same timing as the timing described in the above embodiment,the servo patterns 72B are recorded in the servo band SB3, the servoband SB2, and the servo band SB1 in a state of deviating from each otherat the predetermined intervals in the longitudinal direction LD.

In the example shown in FIG. 22 , the form example has been described inwhich the servo band SB is divided by the plurality of frames 70 alongthe longitudinal direction LD, but the technology of the presentdisclosure is not limited to this. For example, as shown in FIG. 25 ,the servo band SB may be divided by a frame 76 along the longitudinaldirection LD. The frame 76 is defined by a set of servo patterns 78. Aplurality of servo patterns 78 are recorded in the servo band SB alongthe longitudinal direction LD. Similar to the plurality of servopatterns 72 (see FIG. 22 ), the plurality of servo patterns 78 aredisposed at regular intervals along the longitudinal direction LD.

In the example shown in FIG. 25 , servo patterns 78A and 78B are shownas an example of the set of servo patterns 78. Each of the servopatterns 78A and 78B is an N-shaped magnetized servo pattern. The servopatterns 78A and 78B are adjacent to each other along the longitudinaldirection LD, and the servo pattern 78A is positioned on the upstreamside in the forward direction and the servo pattern 78B is positioned onthe downstream side in the forward direction in the frame 76.

As an example, as shown in FIG. 26 , the servo pattern 78 consists of alinear magnetization region group 80. The linear magnetization regiongroup 80 is classified into a linear magnetization region group 80A anda linear magnetization region group 80B.

The servo pattern 78A consists of the linear magnetization region group80A. The linear magnetization region group 80A consists of linearmagnetization regions 80A1, 80A2, and 80A3. The linear magnetizationregions 80A1, 80A2, and 80A3 are disposed in a state of being adjacentto each other along the longitudinal direction LD. The linearmagnetization regions 80A1, 80A2, and 80A3 are disposed in the order ofthe linear magnetization regions 80A1, 80A2, and 80A3 from the upstreamside in the forward direction.

The linear magnetization regions 80A1 and 80A2 are configured in thesame manner as the linear magnetization region pair 74A shown in FIG. 23, and have the same geometrical characteristics as the linearmagnetization region pair 74A. That is, the linear magnetization region80A1 is configured in the same manner as the linear magnetization region74A1 shown in FIG. 23 , and have the same geometrical characteristic asthe linear magnetization region 74A1, and the linear magnetizationregion 80A2 is configured in the same manner as the linear magnetizationregion 74A2 shown in FIG. 23 , and have the same geometricalcharacteristic as the linear magnetization region 74A2. In addition, thelinear magnetization region 80A3 is configured in the same manner as thelinear magnetization region 80A1, and has the same geometricalcharacteristic as the linear magnetization region 80A1.

In the example shown in FIG. 26 , the linear magnetization regions 80A1and 80A2 are an example of a “linear magnetization region pair”according to the technology of the present disclosure; and in such acase, the linear magnetization region 80A1 is an example of a “firstlinear magnetization region” according to the technology of the presentdisclosure, and the linear magnetization region 80A2 is an example of a“second linear magnetization region” according to the technology of thepresent disclosure. In addition, the linear magnetization regions 80A2and 80A3 are also an example of the “linear magnetization region pair”according to the technology of the present disclosure; and in such acase, the linear magnetization region 80A3 is an example of the “firstlinear magnetization region” according to the technology of the presentdisclosure, and the linear magnetization region 80A2 is an example ofthe “second linear magnetization region” according to the technology ofthe present disclosure.

The servo pattern 78B consists of the linear magnetization region group80B. The linear magnetization region group 80B consists of linearmagnetization regions 80B1, 80B2, and 80B3. The linear magnetizationregions 80B1, 80B2, and 80B3 are disposed in a state of being adjacentto each other along the longitudinal direction LD. The linearmagnetization regions 80B1, 80B2, and 80B3 are disposed in the order ofthe linear magnetization regions 80B1, 80B2, and 80B3 from the upstreamside in the forward direction.

The linear magnetization regions 80B1 and 80B2 are configured in thesame manner as the linear magnetization region pair 74B shown in FIG. 23, and have the same geometrical characteristics as the linearmagnetization region pair 74B. That is, the linear magnetization region80B1 is configured in the same manner as the linear magnetization region74B1 shown in FIG. 23 , and have the same geometrical characteristic asthe linear magnetization region 74B1, and the linear magnetizationregion 80B2 is configured in the same manner as the linear magnetizationregion 74B2 shown in FIG. 23 , and have the same geometricalcharacteristic as the linear magnetization region 74B2. In addition, thelinear magnetization region 80B3 is configured in the same manner as thelinear magnetization region 80B1, and has the same geometricalcharacteristic as the linear magnetization region 80B1.

As shown in FIG. 26 as an example, the linear magnetization regions 80B1and 80B2 are an example of the “linear magnetization region pair”according to the technology of the present disclosure; and in such acase, the linear magnetization region 80B1 is an example of the “firstlinear magnetization region” according to the technology of the presentdisclosure, and the linear magnetization region 80B2 is an example ofthe “second linear magnetization region” according to the technology ofthe present disclosure. In addition, the linear magnetization regions80B2 and 80B3 are also an example of the “linear magnetization regionpair” according to the technology of the present disclosure; and in sucha case, the linear magnetization region 80B3 is an example of the “firstlinear magnetization region” according to the technology of the presentdisclosure, and the linear magnetization region 80B2 is an example ofthe “second linear magnetization region” according to the technology ofthe present disclosure.

As an example, as shown in FIG. 27 , the servo pattern recording head WHused for recording the servo pattern 78 is different from the servopattern recording head WH shown in FIG. 24 (that is, the servo patternrecording head WH used for recording the servo pattern 72) in that a gappattern G7 is provided instead of the gap pattern G4, a gap pattern G8is provided instead of the gap pattern G5, and a gap pattern G9 isprovided instead of the gap pattern G6.

The gap pattern G7 consists of straight line regions G7A, G7B, and G7C.The straight line region G7A is used for recording the linearmagnetization regions 80A1 and 80B1 (see FIG. 26 ) in the servo band SB3(see FIG. 25 ), the straight line region G7B is used for recording thelinear magnetization regions 80A2 and 80B2 (see FIG. 26 ) in the servoband SB3 (see FIG. 25 ), and the straight line region G7C is used forrecording the linear magnetization regions 80A3 and 80B3 (see FIG. 26 )in the servo band SB3 (see FIG. 25 ).

The configurations of the straight line regions G7A, G7B, and G7C arethe same as the configurations of the straight line regions G4A, G4B,and G4C shown in FIG. 24 . That is, the straight line regions G7A, G7B,and G7C have the same geometrical characteristics as the straight lineregions G4A, G4B, and G4C.

The gap pattern G8 consists of straight line regions G8A, G8B, and G8C.The straight line region G8A is used for recording the linearmagnetization regions 80A1 and 80B1 (see FIG. 26 ) in the servo band SB2(see FIG. 25 ), the straight line region G8B is used for recording thelinear magnetization regions 80A2 and 80B2 (see FIG. 26 ) in the servoband SB2 (see FIG. 25 ), and the straight line region G8C is used forrecording the linear magnetization regions 80A3 and 80B3 (see FIG. 26 )in the servo band SB2 (see FIG. 25 ).

The configurations of the straight line regions G8A, G8B, and G8C arethe same as the configurations of the straight line regions G5A, G5B,and G5C shown in FIG. 24 . That is, the straight line regions G8A, G8B,and G8C have the same geometrical characteristics as the straight lineregions GSA, G5B, and G5C.

The gap pattern G9 consists of straight line regions G9A, G9B, and G9C.The straight line region G9A is used for recording the linearmagnetization regions 80A1 and 80B1 (see FIG. 26 ) in the servo band SB1(see FIG. 25 ), the straight line region G9B is used for recording thelinear magnetization regions 80A2 and 80B2 (see FIG. 26 ) in the servoband SB1 (see FIG. 25 ), and the straight line region G9C is used forrecording the linear magnetization regions 80A3 and 80B3 (see FIG. 26 )in the servo band SB1 (see FIG. 25 ).

The configurations of the straight line regions G9A, G9B, and G9C arethe same as the configurations of the straight line regions G6A, G6B,and G6C shown in FIG. 24 . That is, the straight line regions G9A, G9B,and G9C have the same geometrical characteristics as the straight lineregions G6A, G6B, and G6C.

The gap patterns G7, G8, and G9 configured as described above arearranged in a straight line along the long side WH1Aa as in theembodiment described above.

The long side WH1Aa of the front surface WH1A is longer than the widthof the magnetic tape MT. The short side WH1Ab of the front surface WH1Ais a length in which all of the gap patterns G7, G8, and G9 arecontained. The long side WH1Aa direction of the front surface WH1Amatches the width direction WD, and the short side WH1Ab direction ofthe front surface WH1A matches the longitudinal direction LD. Thesubstrate WH1 is disposed on the front surface 31 side of the magnetictape MT in a state in which the plurality of gap patterns G and thefront surface 31 face each other and in a state of crossing the magnetictape MT along the width direction WD.

The pulse signals used between the gap patterns G7, G8, and G9 (that is,as shown in FIG. 24 , the pulse signal supplied from the first pulsesignal generator SW4A to the head core WH2A, the pulse signal suppliedfrom the second pulse signal generator SW4B to the head core WH2B, andthe pulse signal supplied from the third pulse signal generator SW4C tothe head core WH2C) are signals delayed by a predetermined time in orderfrom the gap patterns G6, G5, and G4, as described in the aboveembodiment.

In the servo pattern recording step, in a state in which the position ofthe gap pattern G7 corresponds to the position of the servo band SB3,the position of the gap pattern G8 corresponds to the position of theservo band SB2, and the position of the gap pattern G9 corresponds tothe position of the servo band SB1, the magnetic tape MT travels alongthe transport passage SW7 at a regular speed. Moreover, in this state,the pulse signal for a servo pattern 78A and the pulse signal for aservo pattern 78B are alternately supplied to the head core WH2A, thehead core WH2B, and the head core WH2C.

Here, in a case in which the pulse signal for the servo pattern 78A issupplied to the head core WH2A, the head core WH2B, and the head coreWH2C at the same timing as the timing described in the above embodiment,the servo patterns 78A are recorded in the servo band SB3, the servoband SB2, and the servo band SB1 in a state of deviating from each otherat the predetermined intervals in the longitudinal direction LD. Inaddition, in a case in which the pulse signal for the servo pattern 78Bis supplied to the head core WH2A, the head core WH2B, and the head coreWH2C at the same timing as the timing described in the above embodiment,the servo patterns 78B are recorded in the servo band SB3, the servoband SB2, and the servo band SB1 in a state of deviating from each otherat the predetermined intervals in the longitudinal direction LD.

In the embodiment described above, the form example has been describedin which the predetermined interval is defined based on the angle α, theservo band pitch, and the frame length, but the technology of thepresent disclosure is not limited to this, and the predeterminedinterval may be defined without using the frame length. For example, asshown in FIG. 28 , the predetermined interval is defined based on theangle α formed by the interval between the frames 56 having thecorrespondence relationship between the servo bands SB adjacent to eachother in the width direction WD (in the example shown in FIG. 28 , aline segment L3) and the imaginary straight line C1, and the pitchbetween the servo bands SB adjacent to each other in the width directionWD (that is, the servo band pitch). In this case, for example, thepredetermined interval is calculated from Expression (2).

(Predetermined interval)=(Servo band pitch)×tan α  (2)

As described above, Expression (2) does not include the frame length.This means that the predetermined interval is calculated even in a casein which the frame length is not considered. Therefore, with the presentconfiguration, the predetermined interval can be calculated more easilythan in a case of calculating the predetermined interval from Expression(1).

In the embodiment described above, the magnetic tape system 10 has beendescribed in which the magnetic tape cartridge 12 can be inserted andremoved with respect to the magnetic tape drive 14, but the technologyof the present disclosure is not limited to this. For example, even in acase of the magnetic tape system in which at least one magnetic tapecartridge 12 is loaded in advance into the magnetic tape drive 14 (thatis, the magnetic tape system in which at least one magnetic tapecartridge 12 and the magnetic tape drive 14 are integrated in advance),the technology of the present disclosure is established.

In the embodiment described above, the single magnetic head 28 has beendescribed, but the technology of the present disclosure is not limitedto this. For example, a plurality of magnetic heads 28 may be disposedon the magnetic tape MT. For example, the magnetic head 28 for readingand at least one magnetic head 28 for writing may be disposed on themagnetic tape MT. The magnetic head 28 for reading may be used forverifying the data recorded in the data band DB by the magnetic head 28for writing. In addition, one magnetic head on which the magneticelement unit 42 for reading and at least one magnetic element unit 42for writing are mounted may be disposed on the magnetic tape MT.

The description contents and the shown contents above are the detaileddescription of the parts according to the technology of the presentdisclosure, and are merely examples of the technology of the presentdisclosure. For example, the description of the configuration, thefunction, the action, and the effect above are the description ofexamples of the configuration, the function, the action, and the effectof the parts according to the technology of the present disclosure.Accordingly, it is needless to say that unnecessary parts may bedeleted, new elements may be added, or replacements may be made withrespect to the contents described and shown above within a range thatdoes not deviate from the gist of the technology of the presentdisclosure. In addition, in order to avoid complications and facilitateunderstanding of the parts according to the technology of the presentdisclosure, in the description contents and the shown contents above,the description of common technical knowledge and the like that do notparticularly require description for enabling the implementation of thetechnology of the present disclosure are omitted.

In the present specification, “A and/or B” is synonymous with “at leastone of A or B”. That is, “A and/or B” means that it may be only A, onlyB, or a combination of A and B. In addition, in the presentspecification, in a case in which three or more matters are associatedand expressed by “and/or”, the same concept as “A and/or B” is applied.

All documents, patent applications, and technical standards described inthe present specification are incorporated into the presentspecification by reference to the same extent as in a case in which theindividual documents, patent applications, and technical standards arespecifically and individually stated to be described by reference.

(Supplementary Note 1)

A servo pattern recording head comprising a substrate, and a pluralityof gap patterns formed on a front surface of the substrate, in which theplurality of gap patterns are formed on the front surface along adirection corresponding to a width direction of a magnetic tape, amagnetic field is applied to the magnetic tape in response to a suppliedpulse signal to record a plurality of servo patterns in the widthdirection, the gap patterns are at least one straight line region pair,a first straight line region, which is one straight line region of thestraight line region pair, and a second straight line region, which isthe other straight line region of the straight line region pair, areinclined in opposite directions with respect to a first imaginarystraight line along the direction corresponding to the width directionon the front surface, the first straight line region has a steeperinclined angle with respect to the first imaginary straight line thanthe second straight line region, positions of both ends of the firststraight line region and positions of both ends of the second straightline region are aligned in the direction corresponding to the widthdirection of the magnetic tape, positions of the plurality of gappatterns in a longitudinal direction of the magnetic tape are aligned onthe front surface, and the pulse signal generator supplies the pulsesignal with a delay of a predetermined time to each of the plurality ofgap patterns from one side to the other side in a direction in which theplurality of gap patterns are arranged.

What is claimed is:
 1. A servo pattern recording device comprising: apulse signal generator; and a servo pattern recording head, wherein thepulse signal generator generates a pulse signal, the servo patternrecording head has a substrate and a plurality of gap patterns formed ona front surface of the substrate, and records a plurality of servopatterns in a width direction of a magnetic tape by applying a magneticfield to the magnetic tape from the plurality of gap patterns inresponse to the pulse signal, the plurality of gap patterns are formedon the front surface along a direction corresponding to the widthdirection, the gap patterns are at least one straight line region pair,a first straight line region, which is one straight line region of thestraight line region pair, and a second straight line region, which isthe other straight line region of the straight line region pair, areinclined in opposite directions with respect to a first imaginarystraight line along the direction corresponding to the width directionon the front surface, the first straight line region has a steeperinclined angle with respect to the first imaginary straight line thanthe second straight line region, positions of both ends of the firststraight line region and positions of both ends of the second straightline region are aligned in the direction corresponding to the widthdirection of the magnetic tape, positions of the plurality of gappatterns in a longitudinal direction of the magnetic tape are aligned onthe front surface, and the pulse signal generator supplies the pulsesignal with a delay of a predetermined time to each of the plurality ofgap patterns from one side to the other side in a direction in which theplurality of gap patterns are arranged.
 2. The servo pattern recordingdevice according to claim 1, wherein the substrate is formed in arectangular parallelepiped shape, and crosses the magnetic tape in adirection orthogonal to the longitudinal direction of the magnetic tape.3. The servo pattern recording device according to claim 2, wherein thefront surface is formed in a rectangular shape having a long side and ashort side, and a length of the short side is a length in which theplurality of servo patterns are contained.
 4. The servo patternrecording device according to claim 3, wherein the substrate is disposedon the magnetic tape in a posture in which an orientation of the longside and the longitudinal direction of the magnetic tape are orthogonalto each other.
 5. The servo pattern recording device according to claim1, wherein a total length of the first straight line region is shorterthan a total length of the second straight line region.
 6. The servopattern recording device according to claim 1, wherein a geometricalcharacteristic of the straight line region pair on the front surfacecorresponds to a geometrical characteristic in which positions of bothends of one imaginary straight line region of a pair of imaginarystraight line regions and positions of both ends of the other imaginarystraight line region are aligned in the direction corresponding to thewidth direction in a case in which an entirety of the pair of imaginarystraight line regions is inclined with respect to the first imaginarystraight line by inclining, with respect to the first imaginary straightline, a symmetry axis of the pair of imaginary straight line regionsinclined line-symmetrically with respect to the first imaginary straightline.
 7. The servo pattern recording device according to claim 1,wherein a plurality of servo bands are formed on the magnetic tape alongthe width direction, servo patterns corresponding to each other betweenthe servo bands deviate from each other at a predetermined interval inthe longitudinal direction of the magnetic tape, between the servo bandsadjacent to each other in the width direction, and the predeterminedtime is determined in accordance with the predetermined interval.
 8. Theservo pattern recording device according to claim 7, wherein theplurality of servo bands are formed on the magnetic tape along the widthdirection, the servo bands are divided by a frame defined based on atleast one set of the servo patterns, and the predetermined interval isdefined based on an angle formed by the frames that have acorrespondence relationship between the servo bands adjacent to eachother in the width direction and the first imaginary straight line, anda pitch between the servo bands adjacent to each other in the widthdirection.
 9. The servo pattern recording device according to claim 7,wherein the plurality of servo bands are formed on the magnetic tapealong the width direction, the servo bands are divided by a framedefined based on at least one set of the servo patterns, and thepredetermined interval is defined based on an angle formed by the framesthat have no correspondence relationship between the servo bandsadjacent to each other in the width direction and the first imaginarystraight line, a pitch between the servo bands adjacent to each other inthe width direction, and a total length of the frame in the longitudinaldirection.
 10. A magnetic tape in which the plurality of servo patternsare recorded by the servo pattern recording device according to claim 1.11. A magnetic tape cartridge comprising: the magnetic tape according toclaim 10; and a case in which the magnetic tape is accommodated.
 12. Amagnetic tape drive comprising: a travel mechanism that causes themagnetic tape according to claim 10 to travel along a predeterminedpath; and a magnetic head including a plurality of servo readingelements that read the servo patterns on the predetermined path in astate in which the magnetic tape is caused to travel by the travelmechanism, wherein the plurality of servo reading elements are arrangedalong the longitudinal direction of the magnetic head, and the magnetichead is disposed in a posture in which a second imaginary straight linealong the longitudinal direction of the magnetic head is inclined withrespect to a traveling direction of the magnetic tape.
 13. A magnetictape system comprising: the magnetic tape according to claim 10; and amagnetic tape drive on which a magnetic head including a plurality ofservo reading elements that read the servo patterns on a predeterminedpath in a state in which the magnetic tape is caused to travel along thepredetermined path is mounted, wherein the plurality of servo readingelements are arranged along the longitudinal direction of the magnetichead, and the magnetic head is disposed in a posture in which a thirdimaginary straight line along the longitudinal direction of the magnetichead is inclined with respect to a traveling direction of the magnetictape.
 14. A detection device comprising: a processor that is configuredto detect a servo signal, which is a result of reading the servo patternby a servo reading element from the magnetic tape according to claim 10,by using an autocorrelation coefficient.
 15. A servo pattern recordingmethod comprising: generating a pulse signal; and recording, by theservo pattern recording head having a substrate and a plurality of gappatterns formed on a front surface of the substrate, a plurality ofservo patterns in a width direction of a magnetic tape by applying amagnetic field to the magnetic tape from the plurality of gap patternsin response to the pulse signal, wherein the plurality of gap patternsare formed on the front surface along a direction corresponding to thewidth direction, the gap patterns are at least one straight line regionpair, a first straight line region, which is one straight line region ofthe straight line region pair, and a second straight line region, whichis the other straight line region of the straight line region pair, areinclined in opposite directions with respect to a first imaginarystraight line along the direction corresponding to the width directionon the front surface, the first straight line region has a steeperinclined angle with respect to the first imaginary straight line thanthe second straight line region, positions of both ends of the firststraight line region and positions of both ends of the second straightline region are aligned in the direction corresponding to the widthdirection of the magnetic tape, positions of the plurality of gappatterns in a longitudinal direction of the magnetic tape are aligned onthe front surface, and the servo pattern recording method furtherincludes supplying the pulse signal with a delay of a predetermined timeto each of the plurality of gap patterns from one side to the other sidein a direction in which the plurality of gap patterns are arranged. 16.A manufacturing method of a magnetic tape, the method comprising:recording the plurality of servo patterns in the magnetic tape accordingto the servo pattern recording method according to claim 15; and windingthe magnetic tape.
 17. An inspection device comprising: a detectiondevice that is the detection device according to claim 14 and that isused together with the servo pattern recording device according to claim1; and an inspection processor that inspects a servo band on which theservo pattern is recorded in the magnetic tape based on the servo signaldetected by the detection device.
 18. A detection method used togetherwith the servo pattern recording method according to claim 15, themethod comprising: detecting a servo signal, which is a result obtainedby reading the servo pattern by a servo reading element from themagnetic tape according to claim 10, using an autocorrelationcoefficient.
 19. An inspection method comprising: inspecting a servoband on which the servo pattern is recorded in the magnetic tape basedon the servo signal detected by the detection method according to claim18.